Diagnostic Methods

Fluid in the body that resembles serum, can be transudate or exudate.

• a fluid consisting mostly of water moves out of the blood vessel into the body cavity.
• Transudates are formed by two mechanisms. In both cases, capillary permeability is normal, allowing preferential filtration of water over protein. An increase in hydrostatic pressure in the venous circulation without a significant change in osmotic pressure will result in increased fluid production. This mechanism causes effusions in congestive heart failure. A decrease in the concentration of plasma proteins is another common cause of transudates. The decrease in plasma proteins causes a decrease in osmotic pressure. This is a common cause of effusions in malnutrition and cirrhosis.
• Transudates appear as clear pale or yellow fluids.

• a protein-rich fluid in the body cavity.
• The causes of exudate production are more complex, but generally involve two mechanisms. In both cases the usual result is a protein-rich body fluid. The first mechanism is an increase in the permeability of the capillary wall to plasma proteins. This is seen in a variety of inflammatory conditions such as bacterial infection. The second mechanism is the introduction of certain foreign substances into the body cavity. These substances increase the amount of protein and other osmotically active materials in the body cavity, and tend to draw water out of the blood vessel.

A variety of morphologic and chemical findings may be used to differentiate transudates from exudates. Of these, the ratios of total protein or lactate dehydrogenase (LDH) in fluid relative to serum are the most reliable. Differences are also seen in the appearance, white blood cell count, and specific gravity of transudates and exudates. However, significant overlap exists and they should not be relied upon to make this distinction.

The presence of numerous particles in fluid results in a turbid gross appearance. This is commonly seen in bacterial infection where the particles are neutrophils and cell debris. These fluids often have a yellow-green color due in part to neutrophil enzymes, in particular myeloperoxidase. Empyema refers to the presence of pus in a body cavity.

Hemorrhage into a body cavity results in grossly bloody fluid. The red color is a result of the presence of numerous erythrocytes, and may range from light pink to deep red depending on the number of erythrocytes present. Only 0.2% blood is necessary to impart a pink color to a fluid. Situations where a bloody fluid may be seen include malignancy, trauma, or organ infarction. Malignancy is the most common. When severe, hemorrhage into a body cavity can result in the formation of blood clots. Often the clots may be seen grossly. Transudates do not form clots.

Bile imparts a deep green color to body fluids. Bile is formed in the liver, stored in the gall bladder and released into the lumen of the small intestine. A rupture or pathological hole (perforation) through any of these organs can result in the leakage of bile into the abdominal cavity and give rise to a bile-stained fluid.

Chyle is a milky fluid consisting primarly of lymph and triglycerides. It is present in the thoracic duct, a structure which drains lymphatic fluid back into the circulation. Trauma to the thoracic duct or malignancy can result in release of chyle into the pleural cavity. This is known as chylothorax, and is rare. More commonly, a chronic effusion in conditions such as rheumatoid arthritis or tuberculosis may have a chylous appearance. This is called pseudo-chylous effusion and the characteristic appearance is due to cell debris and cholesterol crystals.

Cell counts can be manually determined using the Neubauer Hemocytometer, which consists of two chambers with an overlying coverslip. A dilution of fluid is added into each chamber, and a count is made of the number of each cell type that fall within specified regions.

The cytocentrifuge is used to concentrate cells onto the surface of a glass slide. The slide is then stained and examined microscopically to generate a differential cell count and to evaluate for the presence of malignant cells.

The Wright stain is used for the identification of normal and neoplastic hematopoietic cells on either smears or cytocentrifuge preparations. A slide containing the cells to be stained is first covered with Wright stain and allowed to sit for 2 minutes. An equal amount of buffer is then added and allowed to sit until a green sheen develops, roughly 5-7 minutes, and then quickly rinsed with water. The slide is then allowed to air dry and a coverslip may be applied to prevent damage to the stained cells. The nuclei of cells stain purple or lavender and the cytoplasm stains pale blue (lymphocytes and monocytes) to pink (neutrophils).

• Red blood cells (erythrocytes, RBC) are identified by pink color, small size and absent nucleus
• Increased by hemoconcentration, drugs, altitude, smoking
• Decreased by hemodilution, pregnancy, drugs, sampling technique

Reduced RBCs in a blood sample due to bolus of saline, excess water intake, excess sodium intake

• (Hg or Hgb)
• Transports oxygen and is the main component of RBCs
• Correlates closely to RBC count
• Good indicator of anemia
• Increased by dehydration, polycythemia
• Decreased by anemia, hemorrhage, fluid retention (hemodilution)

• (Hct)
• Reflects the proportion of blood occupied by RBCs
• Measures % by volume of packed RBCs in a whole blood sample
• If HCT is 40% --> a 100 ml sample contains 40 mL of packed RBCs
• Increased by polycythemia, dehydration
• Decreased by anemia, hemodilution, blood loss

• Hemoglobin & Hematocrit
• Similar interfering factors, increasing and decreasing, as with the RBC count
• Verification - Compare RBC, Hgb and Hct
• Rule of three

• leukocytes
• Useful to aid in the diagnosis of infection and inflammation
• Can monitor a pts response to chemo or radiation therapy
• Helps decide if further testing is needed
• Neutrophils, eosinophils, basophils, lymphocytes, macrophages, plasma cells, mesothelial cells.

• An increased white blood cell count above the normal range
• Infection
• Abscess, meningitis, appendicitis, tonsillitis
• Leukemia
• Tissue necrosis
• Burns, MI, gangrene
• Hemoconcentration

• A decreased white blood cell count below the normal range
• Bone marrow depression
• Due to viral infection or toxins
• Seen in influenza, typhoid fever, rubella measles, infectious hepatitis, mononucleosis
• Hemodilution

• 2/3 of WBC
• fine and pale pink granules in the cytoplasma
• type of WBC with segmented nuclei

• coarse and red granules in the cytoplasm
• type of WBC with segmented nuclei

• coarse and purple granules in the cytoplasm
• type of WBC with segmented nuclei

• 1/3 of WBC
• small WBC which has scant, pale blue cytoplasm and a round nucleus
• type of WBC with nonsegmented nuclei

• abundant pale blue vacuolated cytoplasm and larger folded nuclei
• type of WBC with nonsegmented nuclei

• round nuclei with coarse chromatin, and eccentric deep blue cytoplasm with perinuclear clearing
• type of WBC with nonsegmented nuclei

• a cell type unique to serous fluids, as they represent the cells which line serous body cavities. Mesothelial cells are characterized by very round nuclei, often with a single discrete nucleolus, and abundant blue cytoplasm having a frayed cytoplasmic border and perinuclear clearing or "halo". They are often said to have a "fried egg" appearance.
• type of WBC with nonsegmented nuclei

• RBC
• identified by pink color, small size and absent nucleus

• Neutrophil
• fine and pale pink granules in the cytoplasma

• Eosinophil
• coarse and red granules in the cytoplasm

• Basophil
• coarse and purple granules in the cytoplasm

• Lymphocyte
• small WBC which has scant, pale blue cytoplasm and a round nucleus

• Macrophage
• abundant pale blue vacuolated cytoplasm and larger folded nuclei

• Plasma cell
• round nuclei with coarse chromatin, and eccentric deep blue cytoplasm with perinuclear clearing

• Mesothelial cell
• characterized by very round nuclei, often with a single discrete nucleolus, and abundant blue cytoplasm having a frayed cytoplasmic border and perinuclear clearing or "halo". They are often said to have a "fried egg" appearance.

Blood drawn from the body from which no constituent, such as plasma or platelets, have been removed

The clear, yellowish fluid portion of blood, lymph, or intramuscular fluid in which cells are suspended

The clear, yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot

Provides information about 3 types of cells - WBC, RBC and platelets

• Blood chemistry tests help evaluate the body’s respiratory & metabolic status
• Electrolyte levels provide data on body's acid-base balance & fluid balance
• Essential components for basic body functions
• Reflects basic kidney function

Same as BMP but also includes LFT

• Pregnancy test
• Quantitative hCG, measures the amount of hCG in the blood, yields a number vs. positive/negative result

used to detect the presence of bacteria or fungi in the blood, to identify the type present, and to guide treatment. Testing is used to identify a blood infection (septicemia) that can lead to sepsis, a serious and life-threatening complication. Individuals with a suspected blood infection are often treated in intensive care units, so testing is often done in a hospital setting.

• (Prothrombin time)
• Marker of Hepatic Synthetic Function
• (Liver Metabolism)
• A glycoprotein produced in the liver
• Necessary for firm fibrin clot formation
• Measures the time required for a fibrin clot to form
• Elevation indicates hepatic disease, clotting factor deficiency or anticoagulation
• Extrinsic pathway
• Compared with control times
• Variations with methods
• Coumadin therapy - INR replaces PT

• (Partial Thromboplastin Time)
• Intrinsic pathway
• Compared with control times
• Variations with methods
• Heparin therapy - APTT more sensitive

Glucose testing on a non-fasting subject

• A test of platelet function
• Measured as the time it takes for bleeding to stop due to the formation of a platelet plug
• Provided that fibrinogen levels and platelet count is normal, this procedure will detect defective platelet function
• A screening test for inherited and acquired platelet defects

• used to determine an individual's blood group and what type of blood or blood components the person can safely receive. It is important to ensure that there is compatibility between a person who requires a transfusion of blood or blood components and the ABO and Rh type of the unit of blood that will be transfused. A potentially fatal transfusion reaction can occur if a unit of blood containing an ABO antigen to which a person has an antibody is transfused to that person. For example, people with blood group O have both anti-A and anti-B antibodies in their blood. If a unit of blood that is group A, B, or AB is transfused to this person, the antibodies in the person's blood will react with the red cells, destroying them and causing potentially serious complications.
• If an Rh-negative individual is transfused with Rh-positive blood, it is likely that the person will produce antibodies against Rh-positive blood. Although this does not cause problems for the person during the current transfusion, a future transfusion with Rh-positive blood could result in a serious transfusion reaction.
• Rh typing is especially important during pregnancy because a mother and her fetus could be incompatible. If the mother is Rh-negative but the father is Rh-positive, the fetus may be positive for the Rh antigen. As a result, the mother’s body could develop antibodies against the Rh antigen. The antibodies may cross the placenta and cause destruction of the baby’s red blood cells, resulting in a condition known as hemolytic disease of the fetus and newborn. To prevent development of Rh antibodies, an Rh-negative mother is treated with an injection of Rh immune globulin during her pregnancy and again after delivery if the baby is Rh-positive. The Rh immune globulin binds to and "masks" any Rh antigen from the fetus that the mother may be exposed to during her pregnancy and delivery and prevents her from becoming sensitized and developing antibodies against the Rh antigen.
• Blood typing is also used to determine the blood group of potential donors at a collection facility. Units of blood that are collected from donors are blood typed and then appropriately labeled so that they can be used for people that require a specific ABO group and Rh type.

recording of the electrical activity of the heart

An echocardiogram is a test that uses sound waves to create pictures of the heart. The picture is more detailed than a standard x-ray image. An echocardiogram does not expose you to radiation.

• A stress test, also called an exercise stress test, is used to gather information about how well your heart works during physical activity. Because exercise makes your heart pump harder and faster than it does during most daily activities, an exercise stress test can reveal problems within your heart that might not be noticeable otherwise.
• An exercise stress test usually involves walking on a treadmill or riding a stationary bike while your heart rhythm, blood pressure and breathing are monitored.

• substances that are released into the blood when the heart is damaged or stressed. Measurement of these biomarkers is used to help diagnose, risk stratify, monitor and manage people with suspected acute coronary syndrome (ACS) and cardiac ischemia.
• Troponin I or T, CK, CK-MB
• Also myoglobin, BNP, and hs-CRP

used to help detect, diagnose, and evaluate the severity of heart failure. Testing may be performed if a person has symptoms such as swelling in the legs (edema), difficulty breathing, shortness of breath, and fatigue. It can be used, along with other cardiac biomarker tests, to detect heart stress and damage and/or along with lung function tests to distinguish between causes of shortness of breath. Chest X-rays and an ultrasound test called echocardiography may also be performed.

• to determine if a person has a vitamin B12 or folate deficiency. The homocysteine concentration may be elevated before B12 and folate tests are abnormal. Some health practitioners may recommend homocysteine testing in malnourished individuals, the elderly, who often absorb less vitamin B12 from their diet, and individuals with poor nutrition, such as drug or alcohol addicts.
• Homocysteine may be ordered as part of a screen for people at high risk for heart attack or stroke. It may be useful in someone who has a family history of coronary artery disease but no other known risk factors, such as smoking, high blood pressure, or obesity. However, the exact role that homocysteine plays in the progression of cardiovascular disease has not been established, so the utility of the screening test continues to be questioned. Routine screening, such as that done for total cholesterol, has not been recommended.
• Tests for both a urine and blood homocysteine may be used to help diagnose homocystinuria if a health practitioner suspects that an infant or child may have this inherited disorder. In the U.S., all babies are routinely tested for excess methionine, a sign of homocystinuria, as part of their newborn screening. If a baby's test is positive, then urine and blood homocysteine tests are often performed to confirm the findings.

used as part of a cardiac risk assessment to help determine an individual's risk of heart disease and to help make decisions about what treatment may be best if there is borderline or high risk. The results of the lipid profile are considered along with other known risk factors of heart disease to develop a plan of treatment and follow-up. Depending on the results and other risk factors, treatment options may involve lifestyle changes such as diet and exercise or lipid-lowering medications such as statins.

• ordered as a cardiac biomarker, along with troponin, to help diagnose or rule out a heart attack. Levels of myoglobin start to rise within 2-3 hours of a heart attack or other muscle injury, reach their highest levels within 8-12 hours, and generally fall back to normal within one day. An increase in myoglobin is detectable sooner than troponin, but it is not as specific for heart damage and it will not stay elevated as long as troponin.
• Although a negative myoglobin result effectively rules out a heart attack, a positive result must be confirmed by testing for troponin.
• Sometimes, a urine test is ordered to evaluate myoglobin concentrations in those who have had extensive damage to their skeletal muscles (rhabdomyolysis). Blood levels of myoglobin can rise very quickly with severe muscle injury. Urine myoglobin concentrations reflect the degree of muscle injury and, since myoglobin is toxic to the kidneys, reflect the risk of kidney damage.

• (High-sensitivity C-reactive Protein)
• used by itself, in combination with other cardiac risk markers, or in combination with a lipoprotein-associated phospholipase A2 (Lp-PLA2) test that evaluates vascular inflammation. The hs-CRP test accurately detects low concentrations of C-reactive protein to help predict a healthy person's risk of cardiovascular disease (CVD).
• High-sensitivity CRP is promoted by some as a test for determining a person's risk level for CVD, heart attacks, and strokes. The current thinking is that hs-CRP can play a role in the evaluation process before a person develops one of these health problems. Clinical trials that involve measuring hs-CRP levels are currently underway in an effort to better understand its role in cardiovascular events. These studies may eventually lead to guidelines on its use in screening and treatment decisions.

Urine metanephrines testing is primarily used to help detect and rule out pheochromocytomas in symptomatic people. It may also be ordered to help monitor the effectiveness of treatment when a pheochromocytoma is removed to monitor for recurrence. Urine metanephrines testing may be ordered by itself or along with a plasma metanephrines test. Plasma and urine catecholamines testing may also be ordered, either along with urine metanephrines or as follow-up tests. Since catecholamines secretion tends to fluctuate over time, a 24-hour urine test for metanephrines or catecholamines may detect excess production that is missed with the blood test.

• (vanillylmandelic acid)
• used to detect and rule out neuroblastomas in children with an abdominal mass or other symptoms suggestive of the disease.
• A VMA test was once frequently ordered to detect pheochromocytomas, but the preferred tests are now plasma free metanephrines, urine metanephrines, and urine or plasma catecholamine tests. The VMA test may still be ordered along with one or more of these tests to help detect and rule out a pheochromocytoma.

• to screen for and help diagnose Cushing syndrome, a group of signs and symptoms associated with excess cortisol. Blood cortisol testing evaluates both protein-bound and free cortisol while urine testing evaluates only free cortisol, which should correlate with the levels of free cortisol in the blood. Sometimes salivary cortisol is also ordered to help detect Cushing syndrome.
• Blood cortisol is also used to help diagnose adrenal insufficiency and Addison disease, conditions in which the adrenal glands do not function properly.

• Aldosterone and renin tests are used to evaluate whether the adrenal glands are producing appropriate amounts of aldosterone and to distinguish between the potential causes of excess or deficiency. Aldosterone may be measured in the blood or in a 24-hour urine sample, which measures the amount of aldosterone removed in the urine in a day. Renin is always measured in blood.
• These tests are most useful in testing for primary aldosteronism, also known as Conn syndrome, which causes high blood pressure. If the test is positive, aldosterone production may be further evaluated with stimulation and suppression testing.
• Both aldosterone and renin levels are highest in the morning and vary throughout the day. They are affected by the body's position, by stress, and by a variety of prescribed medications.

• (Pulmonary Function Tests)
• A group of breathing tests combined to give an objective evaluation of lung function in disease.
• Assess the degree of airway obstruction
• Measure airway response to allergens
• Quantify airway hypersensitivity
• Determine effect of bronchodilators
• Evaluate effectiveness of long-term treatment of lung disease and progression

• Measurement of gases/ions within the blood that help to evaluate lung/metabolic function and identify any acid-base imbalance
• Components include - pH, O₂, CO₂, HCO₃^-

• to help rule out the presence of a thrombus. Some of the conditions that the d-dimer test is used to help rule out include:
• Deep vein thrombosis (DVT)
• Pulmonary embolism (PE)
• Strokes
• This test may be used to determine if further testing is necessary to help diagnose diseases and conditions that cause hypercoagulability, a tendency to clot inappropriately.
• A D-dimer level may be used to help diagnose disseminated intravascular coagulation (DIC) and to monitor the effectiveness of DIC treatment.

• used to detect and diagnose bacterial lower respiratory tract infections such as bacterial pneumonia or bronchitis. It is typically performed with a Gram stain to identify the bacteria causing a person's infection.
• Sometimes lower respiratory tract infections are caused by pathogens that cannot be detected with routine bacterial sputum cultures. This is either because the pathogens require very specific nutrients to grow in culture or because they grow very slowly. When this is suspected to be the case, specialized tests may be done in addition to or instead of a routine culture to help identify the cause of infection. These additional tests include, for example, an AFB smear and culture to detect tuberculosis and non-tuberculous mycobacteria infections, a fungal culture, or a Legionella culture.

A throat culture should be performed on children or adolescents to confirm the results of a rapid strep test and avoid missing infections that could lead to serious complications, such as rheumatic fever. A throat culture is more sensitive than the rapid strep test, but it may take 24-48 hours for results. According to 2012 guidelines from the Infectious Diseases Society of America (IDSA), confirmatory testing on adults is not recommended since adults have lower rates of strep throat and far lower risk of complications than children.

used to determine whether a person with a sore throat (pharyngitis) has a group A streptococcal infection.

• (Mononucleosis Spot Test)
• used to help determine whether a person with symptoms has infectious mononucleosis (mono). It is frequently ordered along with a complete blood count (CBC). The CBC is used to determine whether the number of white blood cells (WBCs) is elevated and whether a significant number of reactive lymphocytes are present. Mono is characterized by the presence of atypical white blood cells.

typically be done when there are abnormal findings on the physical or chemical examination of urine. It is performed on urine sediment to detect RBCs, WBC, epithelial cells, microorganisms (bacteria, yeast, trichomonads), casts, crystals.

• ordered when symptoms indicate the possibility of a urinary tract infection, such as pain and burning when urinating and frequent urge to urinate. Antibiotic therapy may be prescribed without requiring a urine culture for symptomatic young women who have an uncomplicated lower urinary tract infection. If there is suspicion of a complicated infection or symptoms do not respond to initial therapy, then a culture of the urine is recommended. Pregnant women without any symptoms may be screened for bacteria in their urine, which could affect the health and development of the fetus.
• A urine culture may be ordered with a urinalysis or as follow up to abnormal results on a urinalysis.

• (Blood Urea Nitrogen)
• used, along with the creatinine test, to evaluate kidney function in a wide range of circumstances, to help diagnose kidney disease, and to monitor people with acute or chronic kidney dysfunction or failure. It also may be used to evaluate a person's general health status when ordered as part of a basic metabolic panel (BMP) or comprehensive metabolic panel (CMP).

used along with a BUN (blood urea nitrogen) test to assess kidney function

• used to help evaluate the rate and efficiency of kidney filtration. It is used to help detect and diagnose kidney dysfunction and/or the presence of decreased blood flow to the kidneys.
• In people with known chronic kidney disease or congestive heart failure (which decreases the rate of blood flow), the creatinine clearance test may be ordered to help monitor the progress of the disease and evaluate its severity. It may also be used to help determine if and when kidney dialysis may be necessary.

The ratio of BUN to creatinine is usually between 10:1 and 20:1. An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys, such as congestive heart failure or dehydration. It may also be seen with increased protein, from gastrointestinal bleeding, or increased protein in the diet. The ratio may be decreased with liver disease (due to decrease in the formation of urea) and malnutrition.

the measurement of specific drugs at timed intervals in order to maintain a relatively constant concentration of the medication in the bloodstream. Monitored drugs tend to have a narrow "therapeutic index," a ratio between the toxic and therapeutic doses of medications. For some drugs, maintaining this steady state is not as simple as giving a standard dose of medication. Each person will absorb, metabolize, utilize, and eliminate drugs at different rates based upon their age, general state of health, genetic makeup, and the interference of other medications that they are taking. These rates may change over time and vary from day to day. Changes in the rate may also occur in various disease states or through interaction with other medications.

Measures the amount of alcohol (ethanol) in the blood. 0.08% is considered legally intoxicated in most states

to determine whether a person has illegal or banned substances in his or her body.

• (LFT)
• Albumin
• Total protein (TP)
• Alkaline phosphatase (ALKP, AP, Alk Phos)
• Alanine aminotransferase (ALT, (SGPT))
• Aspartate aminotransferase (AST, (SGOT))
• Bilirubin (Total; Direct)

• Hepatocellular damage - check AST, ALT
• Cholestatis - check Alk Phos, GGT
• Biliary (liver) excretion - check Tbili, Dbili
• Liver synthetic function (Liver Metabolism) - check Albumin, TP, Protime

• Aspartate aminotransferase (AST)
• Serum glutamic-oxaloacetic transaminase (SGOT)
• Marker of Hepatocellular Damage
• A catalytic enzyme found primarily in the heart, liver and muscle tissue, also intestine and pancreas
• Not very specific for liver disease
• Levels elevated with any serious damage to cells
• AST very high in acute pancreatitis
• ETOH=AST>ALT
• Ratio of 2:1 for AST to ALT
• No "L" in cirrhosis (ALT)

• Alanine aminotransferase
• Serum glutamic pyruvic transaminase (SGPT)
• Marker of Hepatocellular Damage
• An enzyme primarily produced by the liver
• Necessary for amino acid production
• Used to evaluate level of liver damage
• In early stages of liver injury, ALT surpasses AST levels and is more specific to the liver
• Found primarily in hepatocytes.
• Released when cells are damaged or destroyed.

• usually only come from a couple of sources:
• Acute viral hepatitis (A,B,C, HSV)
• Acetaminophen toxicity/overdose
• "Shock Liver"; cardiac or surgical event?
• Most other causes don’t produce such high levels.

• Liver biopsy is gold standard
• Biopsy is second only to a good history.
• If a biopsy is obtained, need a sufficiently experienced pathologist to interpret it accurately;

• Marker of Cholestasis
• Enzyme that assists in the transfer of amino acids
• Sensitive for cholestasis & liver infiltration
• Limited specificity
• Found in liver, bone, intestines, pediatrics, placenta
• Isoenzyme available to further evaluate elevated level - determine source
• If elevated with GGT, suggests hepatic origin
• Ideally should be measured fasting
• Only alk phos has variable range depending on age/sex
• Find out if pregnant - found in placenta

• Marker of Cholestasis
• A biliary excretory enzyme that assists in transfer of amino acids and peptides across cell membranes
• Found in the liver, heart, pancreas, kidneys, etc.
• Used to evaluate progression of liver disease and hepatic metastasis
• Progression/regression of carcinoma associated with increasing/decreasing levels
• Screening tool for ETOH abuse
• GGT stays elevated longer than AST or ALT in cases of binge drinking

• An enzyme that aids digestion of complex carbs
• Produced in salivary glands and pancreas
• Inflammation of pancreas causes release of amylase
• Acute pancreatitis:
• Increases in ~2 hrs, peak at ~24 hrs, returns to normal in 2-4 days
• Excreted in the urine
• Order with Lipase for suspicion of pancreas dysfunction, trauma to pancreas, alcoholics, gallstones

• A pancreatic enzyme that changes fats & triglycerides into fatty acids and glycerol
• Rises and falls in tandem with Amylase
• Highly specific for the pancreas
• Acute pancreatitis - Increases in 2-6 hrs, peaks in 12-30 hrs, remains elevated but slowly decreases for 2-4 days
• Order with Amylase
• Amylase also produced in salivary glands so lipase more specific to pancreas

• Marker of Hepatic Synthetic Function
• (Liver Metabolism)
• One of two main proteins in blood (other is globulin)
• Functions to maintain oncotic pressure and transport substances
• Synthesized in the liver and correlates with severity of liver disease
• Decreased in malnutrition
• Reabsorbed by the kidneys, therefore presence in urine → abnl renal function?
• Edema can be caused by decrease in albumin level, decrease in oncotic pressure

• Marker of liver excretion
• Produced in the liver, spleen and bone marrow
• Also a by-product of hemoglobin breakdown
• Total bilirubin increases with jaundice
• Total Bilirubin broken down into Direct (Conjugated) & Indirect (Unconjugated, Free)
• Direct or Indirect rise based on etiology
• Hemolytic anemia – increased total and indirect bili

• Marker of liver excretion
• Excreted by intestinal tract
• Increased with obstructive or hepatic jaundice (impaired excretion)
• Directly measured

• Marker of liver excretion
• Circulates in blood
• Increased with RBC breakdown
• Old RBCs, removed by the spleen, sent to the liver
• Liver "adds" glucuronic acid, making these cells water soluble for excretion; now called direct (or conjugated)
• Calculated from Total Bilirubin and Direct Bilirubin

• (TP)
• Marker of Hepatic Synthetic Function
• (Liver Metabolism)
• Total amount of albumin and globulin in the serum
• Serum proteins are synthesized in the liver and RE system, and constitute >100 different substances
• Decreased in severe hepatic disease and malnutrition

• (Five Prime Nucleotidase)
• A plasma membrane enzyme
• An isoenzyme of Alk Phos found in hepatic parenchyma and bile duct cells
• When coupled with elevated Alk Phos, increased levels are indicative of liver metastasis
• Order for pediatric or pregnant patients

• (Prothrombin time)
• Marker of Hepatic Synthetic Function
• (Liver Metabolism)
• A glycoprotein produced in the liver
• Necessary for firm fibrin clot formation
• Measures the time required for a fibrin clot to form
• Elevation indicates hepatic disease, clotting factor deficiency or anticoagulation
• Extrinsic pathway
• Compared with control times
• Variations with methods
• Coumadin therapy - INR replaces PT

• (NH₃)
• A waste product of nitrogen breakdown during protein metabolism
• It is metabolized by the liver (and excreted as urea by the kidneys)
• Elevated levels may lead to encephalopathy
• Order for someone in a coma

any degenerative disease of the brain, often associated with toxic conditions

• Stool for occult blood (aka - FOBT)
• Cannot be used for vomitus due to pH
• Has its own developer solution
• Indicates bleeding somewhere in the GI tract
• Useful for Colon cancer screening
• 3 days prior to and during the test period - do not eat red meat
• 7 days prior to and during the test period - avoid NSAIDs (ie- Ibuprofen)
• If taking Aspirin, limit = 1 adult aspirin per day.

• Vomitus for occult blood
• Cannot be used for stool testing
• Has its own developer solution
• Indicates bleeding in the upper GI tract only
• Not useful for cancer screening

• Radioactive labeled urea ingested by patient
• If urease activity present then radioactive CO2 is exhaled
• Radioactivity is measured
• Highly sensitive

• A stool culture is indicated for:
• Persistent diarrhea
• Bloody diarrhea with fever
• Travel to endemic areas
• Immunocompromised patient with diarrhea
• Known exposure to enteric pathogens
• Recent Antibiotic use (antibiotic-associated diarrhea - AAD)
• Rules out:
• Salmonella, Shigella, E.coli, Campylobacter species and yeast. All other pathogens require specific request based upon clinical suspicion

• a spore-forming, gram-positive anaerobic bacillus, that produces two exotoxins. It is a common cause of antibiotic-associated diarrhea.
• It accounts for up to 25% of all episodes of AAD.

• 3 Separate Specimens collected 2-3 days apart
• Specific clinical information should be provided as preparation differs for different organisms.

• Scotch Tape Test for Enterobius vermicularis (aka - Pinworm)
• Presenting complaint is perianal itching
• Most often seen in small children
• Day care increases risk
• Organism is pinworm
• For tapeworms the whole stool specimen is required.
• Commercial kits available $$$$
• Use tongue blade and clear tape
• Early morning
• Touch to several places around the anus
• Attach to glass slide
• Put in clean container

• used to help detect and/or diagnose acute liver infection and inflammation that is due to one of the three most common hepatitis viruses - hepatitis A virus (HAV), hepatitis B virus (HBV), or hepatitis C virus (HCV).
• Hepatitis A antibody, IgM
• Hepatitis B core antibody, IgM
• Hepatitis B surface Ag
• Hepatitis C antibody
• HAV antibody, total
• HBV core antibody, total
• HBV surface antibody

• Assessment for fat malabsorption
• A number of diseases of the pancreas & GI tract are characterized by fat malabsorption
• The Test:
• A random fecal specimen is submitted to the lab and examined under the microscope after staining with a Sudan dye ("Sudan staining")
• Visible amounts of fat indicate malabsorption and this is then quantified

• A specimen of feces is tested for acidity
• Human feces is normally alkaline
• An acidic stool can be indicative of a digestive problem such as lactose intolerance or a contagion such as E. coli or Rotavirus

• Normally, there are no WBCs in stool.
• Large numbers of WBCs in the stool may be seen in chronic bacillary dysentery, chronic ulcerative colitis, colonic abscess
• Monocytes are seen in Typhoid Fever
• Neutrophils are seen in invasive E.Coli diarrhea, Salmonella, Shigellosis

• A powerful electric current is applied to a negatively charged cathode which "boils" off high energy electrons.
• These electrons are then attracted by, and impact a positively charged anode at high speed. A large amount of energy is released as a result of this impact, some of which is in the form of X-radiation.
• The X-rays produced then travel out of the "tube" and through the patient.
• The radiation that penetrates the patient is then captured by a device(s) designed to produce an image.
• The varying wavelengths or "strength" of the penetrating radiation, making it through the patient, is key to how the collection device will determine the images appearance.

• Chest - Infiltrative processes, infectious processes, pulmonary neoplasms, pulmonary emboli, atelectasis, Heart size and diaphragmatic position.
• Abdominal - Bowel OBS., perforated viscous ("free air"), organomegally, large abdominal masses or fluid collections/ascites.
• Skeletal - Bony fractures, dislocation, arthritic processes, bony neoplasms, growth and/or malalignment disorders.

• Radiation exposure
• As low as reasonably achievable

• Ultrasound is produced by what is known as the piezoelectric effect.
• A special crystal (called a piezoelectric crystal) is within the ultrasound probe and when excited by an electric current vibrates thus, producing sound.
• The sound is produced in a frequency range much higher then the human ear can hear (>20,000 Hz). This is called ultrasound.
• Sound waves travel from the probe through the patient and back to the probe again through a coupling gel applied to the patient’s body.
• The returning sound waves varying speeds are interpreted by a sophisticated computer and "real-time" images are produced.
• Ultrasound waves are disrupted when they come into contact with air and are completely attenuated when they come into contact with bone. Therefore, ultrasound is unable to image structures surrounded or associated with air and/or bone.
• Ultrasound waves travel through water and soft tissue well. Therefore, any structure made up of these is potentially "fair game" for ultrasound provided they are not affected by air or bone.

• Abdomen - All abdominal organs and structures with the exception of bowel.
• Pelvis - Both male and female GU organs.
• Heart/Vessels - Most arteries and veins of moderate and substantial size throughout the body. This is done by a means called doppler which allows us to see & measure blood flow within the vessel and diagnose vascular diseases. Referred to as a duplex scan.
• Thyroid gland.
• Neonatal brain through fontanel
• Fluid Collections - Including the abd., chest & extremities.
• Breast - Including axillary lymph nodes. *Not to be used as a screening tool for the breast.
• Obstetrical - To asses the proper development and anatomical structure of the fetus.

• (Dual Energy X-ray Absorptometry)
• Low dose X-rays are generated and passed through the patient’s spine, hip(s) and/or forearm(s).
• The differing energies of radiation which passed through the patient are received by sensitive detectors within the scan arm.
• This information is then sent to a computer which determines the structures relative bone mass which is reported in cubic cm.
• This becomes the patients Bone Mineral Density (BMD) value.
• This numeric BMD value is then converted into T & Z scores, which are then compared to a reference table and classified as normal, osteopenia or osteoporosis. These tables are most often based on studies performed by the WHO or NOF.

• Osteopenia/Osteoporosis
• Recent advancements allow capable DEXA units to classify and grade types of spinal compression fractures and determine total body mass indices (BMI).

• Computerized Axial Tomography (CAT Scan)
• X-ray’s travel through the patient as the X-ray tube spins in 360° circles around the body (Called Tomography).
• Detectors at the opposite end of the tube capture the x-rays that have traveled through the patient and interpret their differing wavelengths or strengths.
• A powerful computer then interprets these wavelengths and digital, cross sectional type images are constructed.
• Tumors suck up contrast to show whiter on CT due to increased blood flow to it.
• Don't use contrast for kidney stones (looking for white horse in a snow storm)

• Brain
• Sinuses
• Organs & tissues of the face & neck
• Chest
• Abdomen
• Pelvis
• Soft tissues of the extremities
• Joints (especially following arthrography)
• Blood vessels or heart using a technique known as CT-angio (CTA)
• Spinal cord following myelography.

• CT has limitations detecting the presence of small to moderate sized intra-luminal lesions within the GI tract.
• CT is also somewhat limited when trying to decipher between purely cystic versus solid lesions. (This is something ultrasound is really good at doing!)

• The patient is placed into a powerful, enclosed or open magnetic environment (at least 30,000x greater than Earth’s magnetic field)
• This field causes uniform alignment of charged ions inside the cell into positive and negative poles. The ions are usually randomly aligned in haphazard fashion in the cells.
• Hydrogen atoms are highly influenced by magnetic fields and all the cells in our bodies have H⁺ atoms within them.
• When the magnet is turned on and off the cells resonate and this resonation can be detected by sensors in the unit.
• Tissues within our bodies resonate differently. These differing resonations are then captured by detectors and a powerful & sophisticated computer interprets the information thereby creating an image.

• Pacemakers
• AICD's
• Cerebral aneurysm clips prior to 1990.
• Neuro-stimulators
• Metal joint replacements degrade the image greatly making scanning in or around these objects difficult.
• Any other inplantable and/or non-removable metallic device is suspect. Ask the MRI technologist at the medical imaging center if you have any questions concerning a potentially hazardous foreign body or device.
• Metformin and contrast - nephrogenic systemic fibrosis (NSF)

• Brain & Spinal Cord
• Nerves
• Skeletal System & Joints.
• Abdomen/Pelvis
• Chest
• Soft tissues of the extremities.
• Blood vessels (MRA)
• Gallbladder and bile ducts. (MRCP)
• Breast
• Prostate
• Heart
• Joints post arthrography

• Radioactive substances for example, Tc99m, Io131, Ga67 (depending on the type of exam requested) are injected via an IV.
• The radioactive elements are "tagged" with a particle or substance which is utilized by specific cells in the body.
• The radioactive substance then accumulates within cells that utilize that particular element or particle.
• The radioactive energy is emitted from the cells and received by detectors (gamma-camera) surrounding the patient.
• The information is then converted into an image.
• For example, the skeletal system utilizes phosphates during normal metabolism. So Tc99m is tagged with MDP (monodiphosphotase particles). The skeleton absorbs the MDP particles which subsequently carries the Tc99m into the bones. Because of this a bone scan can be performed.

• Skeletal system - Primary tumor or mets
• Pulmonary system - Pulmonary embolism
• Heart - To determine the extent of heart muscle damage.
• Infectious or inflammatory processes- Abscess
• Lymphoma
• Kidneys - To asses renal function.
• Thyroid - Detects thyroid masses/nodules and classify them as "Hot" or "Cold".
• GI & GB studies - To assess gastric emptying & GB Func. (radioactive scrambled eggs)
• Sentinel lymph node(s) identification - Used to identify the primary node(s) which provide initial drainage from an abnormal region in the body

For patients with hyperthyroidism Large amounts of Io131 can be used to ablate the thyroid gland with radiation as an alternative to surgical removal.

• A low dose of radiation is generated via an X-ray tube and passed through the breast tissue.
• A film or digital collection device captures the radiation which has passed through the breast tissue and a detailed image is produced.
• The breast is placed into a compression device that squeezes the breast tightly. This is necessary to limit the amount of radiation to the patient and to increase image detail. It also allows for reproducibility between examinations to assure that the breast is being evaluated the same way each time.

• Radioactive Fl is labeled with glucose compounds which are injected into the patient.
• These compounds are then metabolized by the cells within the patient’s entire body.
• Although glucose is used by all cells, more glucose is used by cells with increased metabolism.
• Because cancer cells are highly metabolic and therefore, use more glucose than neighboring cells, they are easily seen on a PET scan.
• Detectors surrounding the patient receive the information emanating from the cells and determine which cells have a greater amount of the radioRx within them.
• An image of the entire body is produced and any areas of higher glucose metabolism are easily identified.
• Same technique as nuclear medicine
• Chiefly used to detect tumors
• CT and PET scanner in one, get anatomy and physiology images

• PET is primarily used in the field of medical imaging to discover the presence of and/or extent of cancer.
• Types of cancer that can be revealed by PET include:
• Lung, colo-rectal, breast, prostate, and/or lymphatic.
• PET is also used to evaluate the function of the brain of those with Alzheimer's disease, Parkinson's disease and/or seizure disorders.
• PET also plays a role in the research of psychiatric and behavioral disorders.

• X-rays are produced from a conventional X-ray tube continuously.
• The varying wave lengths of the X-rays that pass through the patient are collected by a device called an image intensifier which then converts this information into a real time, movie like image on the monitor.
• Fluorsocopy is commonly used to image dynamic structures or when one needs to perform a procedure that requires continuous image guidance.
• The use of contrast agents during fluoroscopic tests/procedures is also common.

• GI tract - Video swallowing evaluation, Esophagram, Upper GI Series (UGI), Small bowel follow through (SBFT), Barium enema (BE).
• Urinary system - Cystogram, Voiding cystourethrogram (VCUG).

• Contrast agent
• Barium is an inert substance that has a high atomic mass (density). When mixed with water and swallowed or infused trans-rectally the substance coats the lumen of the GI tract (esophagus, stomach, and/or intestines). The high atomic weight of the Barium attenuates the X-ray beam thus allowing us to see the coated structures.

• Certain types can be injected into the vascular system, spinal cord, bile ducts, uterine cavity etc.
• They can also be used if bowel perforation is suspected because they will be absorbed by the peritoneum safely. Barium does not get absorbed by the body and if spilled into the abdominal cavity can cause peritonitis.
• Water soluble contrast agents when injected via IV can have a nephrotoxic effect on the kidneys. Because of this, those individuals with compromised renal function (elevated BUN creatinine levels) or history of renal failure should not be used.
• Allergic reaction to water soluble contrast is also a potential problem, although this is much less of a risk today. Patients who have a known allergy can be pre-treated with Prednisone and/or Benedryl prior to a study to prevent allergic reaction.
• Water soluble contrast material is filtered by the kidneys and excreted quickly. This allows for evaluation of the urinary system.

• Used to evaluate the swallowing function of the oro-pharynx, hypo-pharynx and cervical esophagus ONLY! The patient ingests varying consistencies of barium laden materials to see if they can masticate properly, form a bolus and thus, swallow effectively and safely.
• The test also is used to establish the presence and severity of aspiration during swallowing which can cause pneumonia. If aspiration is present airway protective maneuvers and foods of different consistency can be experimented with to see if they help prevent the aspiration from occurring.
• Usually performed with a licensed speech therapist who teaches the patient airway protective maneuvers and suggests changes to the patients diet to aid in swallowing.
• Not the same as an esophagram!

• The patient ingests Barium at a rapid pace to visualize the entire esophagus.
• The study can determine the presence of aspiration, swallowing abnormality, PUD, mass, stricture, obstruction, hiatal hernia, diverticula, perforation and/or gastro-esophageal reflux.

• (UGI)
• Used to evaluate the esophagus and stomach.
• Can evaluate everything that an esophagram can plus:
• gastric PUD, masses, polyps, inflammation (gastritis), perforation, and/or outlet obstruction.

• (SBFT)
• Used to evaluate the small bowel for IBD (Crohn's disease), tumor, adhesions, stricture, or obstruction.
• The entire upper GI tract (esoph., stomach & small bowel) can be evaluated by ordering a UGI/SBFT study if necessary.

• Contrast is infused trans-rectally to allow for visualization of the colon.
• Can be uncomfortable.
• Used to identify the presence of colonic polyps/masses, IBD, diverticulosis(itis), perforation, stricture, and/or obstruction.
• Most common cause of bowel obstruction is adhesion from previous surgery
• Worldwide it’s hernia

• Water soluble contrast is injected into the body via an IV. The contrast is then filtered by the kidneys and evaluation of the renals, ureters and bladder can be made.
• Provides information regarding the function of the kidneys also.
• Renal - masses, cysts, stones, perforation or OBS.
• Ureters - Stones, strictures, perforation or OBS.
• Bladder - Stones, masses, perforation, OBS.

• Interventional radiology utilizes fluoroscopy, ultrasound, CAT scan and/or mammographic technologies to perform invasive tests and therapeutic procedures on patients. The procedures performed allow us to limit the recovery time, discomfort and risk to the patient. The procedures are typically much less costly and safer than some related surgical options. The use of image guidance increases safety, accuracy and efficiency.
• Special needles, guide-wires, ports, infusion catheters, and drainage tubes are commonly used to perform the necessary interventions.

• Guided organ/tissue biopsy
• Fluid collection drainage
• Abscess drainage
• Urinary drainage tube/stent placement
• Vascular angiography
• Vascular angioplasty, stent placement & embolization
• Vascular access device placement (chest/arm ports, PICC lines, dialysis catheter placement, triple lumen etc.)
• Hepatic bypass (TIPSS)
• Tumor ablation/embolization (liver,uterus etc.)
• Vertebroplasty
• Myelography, Discography
• Therapeutic joint injection and arthrography

• ventilation/perfusion ratio
• scan for Pulmonary Embolism
• V – Ventilation Image made with radioactive gas or aerosol (xenon 133) inhaled by patient
• Q – Perfusion Image made with radioisotope tagged albumin injected via IV
• A normal scan rules out presence of PE
• A low probability cannot rule out PE but when combined with the absence of DVT it is doubtful that there is a PE
• An intermediate probability scan is not helpful. Further evaluation should be considered. Angiography?
• A high probability Scan indicates an 85% chance of PE

• 1. Vascular Phase
• 2. Platelet Phase
• 3. Coagulation Phase
• 4. Fibrinolytic Phase

• Smallest formed elements in blood
• Promote coagulation in the intrinsic clotting pathway by helping to form a hemostatic plug

• an abnormal decrease in number of platelets
• Hypoplastic bone marrow, leukemia, folic acid deficiency
• Increased platelet destruction

• an abnormal increase in the number of platelets
• Hemorrhage, infection, cancers, iron deficiency anemia, inflammatory disease, surgery, pregnancy
• Returns to normal after recovery

• (HCO₃^-)
• Released from the pancreas
• Biologic levels are controlled through the kidneys, indicating metabolic control
• Bicarbonate itself is an intermediate form of carbonic acid (H₂CO₃)
• Plays a crucial role in the physiologic pH buffering system
• Normal HCO₃^- ranges from 22-26 mmol/L
• HCO₃^->26 is alkalosis
• HCO₃^-<22 is acidosis

• Step 1 - Look at the pH and determine if it is acidotic, alkalotic, or normal
• Acidosis<7.35, Alkalosis>7.45
• Step 2 - Look at the pCO₂ and determine if it is acidotic, alkalotic, or normal
• Remember pCO₂ indicates respiratory function
• Acidosis>45, Alkalosis<35
• Step 3 - Look at the HCO₃^- and determine if it is acidotic, alkalotic, or normal
• Remember HCO₃^- indicates metabolic function
• Acidosis<22, Alkalosis>26

• pH>7.45
• Caused by loss of CO₂ (<35 mmHg)
• Shifts the equation to the left as less CO₂ is available
• Etiologies - Hyperventilation (excessive amounts of deep breathing)

• pH<7.35
• Retaining too much CO₂ (>45 mmHg)
• Shifts the equation to the right as increased CO₂, increases H₂CO₃, which in turn increases H⁺
• Etiologies - COPD, Drug overdose (narcotics), Hypoventilation
• Narcotics depress respiratory system

• pH>7.45
• Due to loss of acids from the body or the production of bases
• Simply put, the loss of too much H⁺ or the addition of a base, similar to HCO₃^-, causes metabolic alkalosis
• Etiologies - Diuretic abuse, Vomiting
• Urine is acidic normally so peeing out too much can lead to loss of H⁺

• pH<7.35
• Due to loss of bases or production or ingestion of acids
• An increase in H⁺, or a loss of a base lead to metabolic acidosis
• Etiologies - Diarrhea, Overexertion
• Overexertion leads to insufficient supply of O₂ to the muscles which leads to a build up of lactic acid, in excess amounts it exceeds the buffering capacity of the blood (due to anaerobic process)
• Loss of water so loss of bicarbonate along with it
• MUDPILES:
• Methanol (paints, plastics, fuel)
• Uremia
• Diabetic ketoacidosis
• Propylene glycol (food preservative)
• Isoniazid (Tb drug)
• Lactic acidosis
• Ethylene glycol (antifreeze, plastics)
• Salicylates (Aspirin)

• Asthma diagnosis & severity
• COPD patients - Emphysema, Chronic Bronchitis
• Bronchodilator effectiveness
• Exercise induced or hypersensitivity to allergen?
• Reduced FEV₁/FVC
• Reduced FEF 25-75%
• Reduced PEF

emphysema

chronic bronchitic

• Cystic fibrosis
• Interstitial disease - Sarcoidosis, idiopathic pulmonary fibrosis, silicosis; Work related disease - black lung, asbestosis
• Track progression of disease
• Normal or increased FEV₁/FVC
• Normal FEF 25-75%
• No change in PEF
• Reduced FVC
• Volumes decrease instead of flows

• total lung capacity
• VC + RV

• vital capacity
• total volume for gas exchange
• full expiration, aids minute volume if they need to cough, secretions
• IRV + V_T + ERV

• residual volume
• what’s left after full expiration

• inspiratory capacity
• IRV + V_T

• functional residual capacity
• ERV + RV

• expiratory residual volume
• forced expiration

• inspiratory reserve volume
• what can be inhaled in a deep breath

• tidal volume
• volume used during resting breathing

• Minute volume = resp rate x tidal volume (V_T)
• Controls CO₂ level

• The forced expiratory volume achieved during the first one-second period
• Normal range = >80% predicted

• the ratio of volume During the 1st second of expiration in comparison to the total vital capacity
• A better predictor of obstruction than comparing FEV1 to predicted value

• Forced expiratory flow rate over the middle 50% of the FVC volume.
• Signals disorders in smaller bronchi and larger bronchioles because it measures flow at a later point in the maneuver
• Otherwise known as maximal mid-expiratory flow

peak expiratory flow rate

• (Slow Vital Capacity)
• Performed using the same maneuvers as a forced vital capacity only modifying the force exerted during expiration.
• Used to allow those patients with severe air-trapping to possibly release more of their ERV in order to get a more accurate reading of their true volumes

More severe than Hyper-inflation, volume is unable to escape due to collapsing airways.

Considered less severe than air-trapping, excess volume can usually be exhaled with extended expiratory time and slower flow.

• Method of testing lung volumes
• Otherwise known as the 'body box". An airtight, telephone booth style box with a mechanical shutter which can occlude at any phase of respiration.
• Based on Boyle’s Law - P₁V₁=P₂V₂ when temperature is constant.
• This equation allows us to establish patient’s lung volumes due to change in gas pressure or volume after establishing a known set of parameters.

• Based on patient’s ability to cooperate as 100% oxygen is inhaled for several minutes through a 2-way valve (7 minute max). Exhaled gas is measured for nitrogen content after each breath until N₂ is <1.5% for 3 breaths.
• FRC is calculated from final nitrogen concentration which allows us to establish RV and TLC.

• (DLCO)
• Testing the ability of oxygen and carbon dioxide to diffuse across the alveolar membrane.
• Involves SVC maneuver followed by fast inspiration and breath hold for ten seconds with slow exhalation to follow.
• Carbon Monoxide and helium (trace amounts) are used to perform the test due to increased affinity to hemoglobin.

• Used to determine presence & severity of Asthma or reversible airways disease.
• Pt given 4 preset incrementing dosages of methacholine followed by spirometry after each dosage.
• Dosage set by American Thoracic Society.
• Looking for decrease of 20% in FEV1 within the first 3 dosages.

• Use spirometry to evaluate for obstructive or restrictive process.
• Use Lung volumes to confirm your answer.
• Did patient give a good effort?
• Are the post bronchodilator treatments effective?
• Does diffusion seem to be a problem?
• Consider these values along with pt. history, signs and symptoms to determine possible disease states and progression of disease.

• Trending Alveolar ventilation & V/Q imbalances caused by pulmonary or Cardio disorders
• Used to estimate Physiological dead space
• Detect extubation or esophageal intubation
• Assess blood flow in CPR
• Determine Peep levels
• Evaluate airway Obstruction

• Deep breathing by the patient to accomplish hyperinflation evidenced through use of a flow or volume oriented spirometer
• The goal is to prevent atelectasis post-operatively
• The patient is expected to achieve at least 12 ml/kg to reverse atelectasis
• Atelectasis can lead to pneumonia

• Determines the severity of asthma
• Checks response to treatment during an acute asthma episode
• Monitors progress in treatment of chronic asthma and provides objective information for any possible adjustments in therapy
• Detects worsening in lung function and thereby helps avoid a possible serious flare-up in asthma with early intervention

• Largest solid organ in the body
• Performs over 500 chemical processes
• Produces over 160 different proteins
• Makes clotting factors for the blood
• Stores & releases sugar as glycogen
• Metabolizes (recall CYP 450 isozymes!), detoxifies, synthesizes

• Refers to any swelling, inflammation, or irritation of the liver
• More than 100 known causes including:
• Viruses, alcohol, enzyme deficiencies, Genetic disorders, licit & illicit drugs, toxins, Hypotension (shock liver/reperfusion)
• Viral hepatitis (A,B,C,D,E,G),
• Also CMV (Cytomegalovirus); HSV (Herpes Simplex); WNV (West Nile Virus)
• Drug-induced hepatitis (acetaminophen)
• Alcoholic hepatitis
• Autoimmune hepatitis
• Ischemic hepatitis

• May include any of the following:
• Fever
• Malaise; Fatigue
• Nausea & Vomiting
• Anorexia
• Jaundice
• Abdominal RUQ Pain
• Dark Urine

• Hepatitis A --> fecal – oral route
• Hepatitis B, C --> serum + blood products; saliva, semen, vaginal secretions
• Increased risk in IVDUs, illegal drugs, unsanitary practices, health care workers (unsafe practices)

• Food, water borne; heat labile
• Fecal - oral contamination; contagious
• Usually self limited, lasting days to weeks
• 99% spontaneous recovery, no treatment
• Tests:
• HAV IgM antibody = acute infection
• HAV total antibody (IgM + IgG) = exposure only (could be post-infection or post-vaccination)

• Blood, semen, saliva, vaginal secretions
• Highly contagious; sexually transmitted
• 90-95% self limited over 6 months
• Chronic infection is > 6 months
• DNA virus - incorporates into host with chronic infection.

• Blood borne, not in food or water; not highly sexually transmitted.
• Not highly contagious.
• 20% self-clearing; 80% chronicity
• RNA virus - does not incorporate into host.
• #1 identified cause of need for liver transplant.

• Inflammation that lasts long enough will create fibrosis
• Extreme fibrosis is called cirrhosis.
• Cirrhosis can be either compensated or decompensated
• Compensated cirrhosis can be subtle (in its presentation)
• Decompensated cirrhosis is more obvious

• Implicated in diseases of the upper GI Tract including:
• chronic active gastritis
• gastric ulcer
• duodenal ulcer
• non-ulcer dyspepsia
• gastric adenocarcinoma
• MALT Lymphoma (mucoid associated lymphoid tissue)

• viral
• The pathogens:
• Rhinovirus and coronavirus most common
• Ebstein-Barr virus (EBV) –-> infectious mononucleosis, dx of exclusion
• Coxsackie A and herpes virus, the most common cause of ulcerative pharyngitis
• HISTORY:
• Classic symptoms --> Fever, throat pain, dysphagia
• Most likely concurrent URI symptoms of rhinorrhea, cough, hoarseness, conjunctivitis & ulcerative lesions
• Insidious, low grade fever, usually lacks exudates
• PHYSICAL EXAM:
• Non specific viral pharyngitis – unimpressive
• Marked erythema typically occurs with adenoviral infection. In contrast, rhinoviral and coronaviral infections are not likely to manifest with severe erythema
• Exudates with adenovirus, look for conjunctivitis
• Coxsackie – vesicles/ulcerative lesions present on pharynx or posterior soft palate

• (Mononucleosis)
• Classic Triad – fever, pharyngitis, adenopathy
• History:
• Severe sore throat, fatigue/myalgia/malaise, anorexia secondary to pain, fever
• Sick contacts? --> transmitted via infected saliva
• PE:
• White exudates covering erythematous pharynx and tonsils, cervical adenopathy*, possible HSM, Palatal petechiae, Occasionally a maculopapular rash
• *Mono presents atypically in adults:
• 40% inguinal adenopathy
• 60% cervical adenopathy
• Diagnostic studies (blood tests):
• Heterophile agglutination test (Monospot)
• Lymphocytic predominance (>50% of diff) and >10 % atypical lymphocytes on blood smear
• Antibodies to EBV antigens:
• Acute phase antibodies - xEA, xIgM VCA
• Convalescent antibody - xIgG VCA
• Recovered State - xIgG VCA, xEBNA

• Strep pyogenes (group A ß-hemolytic, “GAS”)
• Neisseria gonorrhea
• Haemophilus influenzae
• Corynebacterium diphtheriae
• Borrelia vincenti
• Mycoplasma
• Chlamydia
• Signs and symptoms:
• Inflammation of the pharynx & lymphoid tissue results in fever, sore throat, malaise, and HA
• Absence of viral symptoms
• Classic findings for GAS throat include:
• High fever
• Tonsillar exudates
• Anterior cervical adenopathy
• Diagnostics:
• Throat swab (x2 together!) is performed
• Rapid Strep Test
• Takes about 10–20 minutes
• Positive results are definitive
• 70-90% sensitive
• Negative results should be confirmed with a culture
• Gold standard --> culture of swab of tonsils and posterior pharynx
• 90-99% sensitive
• Takes about 24 – 48 hours
• More accurate than Rapid Strep Test

• History consistent with oral GC exposure
• No specific PE findings --> Sore throat, difficulty swallowing, fever, tender, swollen lymph nodes in the neck
• Recurrent sore throats not responsive to usual Abx’s
• Perform throat culture

• SYMPTOMS:
• Sore throat, dysphagia, weakness, malaise
• SIGNS:
• Toxic appearance, fever, tachycardia (out of proportion to fever), pharyngeal erythema
• Gray-white tenacious exudate or "membrane" occurs at tonsillar pillars and posterior pharynx; Leaves focal hemorrhagic raw surface when removed
• Cervical lymphadenopathy can be significant
• "Bull neck"

• Signs and symptoms:
• Often necessary to differentiate influenza from the common cold
• Symptoms include high fever (up to 104° F), chills, HA, exhaustion, generalized aches, cough, +/- GI complaints
• Patients occasionally report clear nasal congestion, sneezing, and sore throat
• Abrupt onset
• Diagnosis:
• Routinely based on clinical signs & symptoms
• PE shows mild pharyngeal erythema, cervical adenopathy, clear nasal discharge
• Nasopharyngeal swab or aspirate can be obtained for a rapid antigen test
• Chest xray usually normal

• Most commonly due to H. influenzae
• Other organisms include:
• S. pneumoniae, Staph aureus, Candida albicans, HSV
• 3D’s --Drooling, Dysphagia and Distress
• difficulty swallowing and breathing, tripoding, muffled voice
• DO NOT ATTEMPT THROAT CULTURE
• Diagnosis:
• Lateral neck x-ray --> shows "thumbprint sign" of narrowed and thickened epiglottis
• Epiglottis direct visualization via laryngoscopy
• "cherry red" appearing epiglottis
• Perform ONLY in OR after airway is secure
• Obtain surface cultures of the epiglottis
• Blood cultures are positive for causative agent in 90% of cases by some reports

• PPD - Purified Protein Derivative
• Measure the area of induration not the area of erythema
• ≥ 5 mm, for highest risk group
• Immune compromised --> Transplant, HIV, chronic steroid use
• Close contact with TB
• Abnormal CXR
• ≥ 10 mm, ‘other’ risk factors
• IVDU, homeless, hospital/prison/shelter
• Recent immigrant
• DM, malignancy, malnutrition, renal failure
• ≥ 15 mm, no known risk factors

• Clinical Manifestations:
• Cough
• Fever
• Chest discomfort or pain
• Dyspnea
• Sputum production
• Diagnostics:
• CXR - The gold standard – ideally PA and lateral
• Consolidation? Atelectasis? Pleural effusion?
• Bronchoscopy with biopsy/lavage
• PCP, TB
• Percutaneous needle aspiration
• 5% risk of pneumothorax
• Thoracentesis

• Viral - Influenza, RSV, Adenovirus, Parainfluenza
• Atypical Pneumonias - Legionella (3-30%), Mycoplasma (5-35%)
• Pneumocystis (PCP)
• Bacterial - Pneumococcal (30-75%), Other Streps, A&B, S.aureus (3-10%), H.influenzae (6-12%), Klebsiella pneumoniae, Anaerobes

• History:
• Most common cause of CAP
• Elderly or chronically ill pt
• Alcoholism, smoking, nursing home, college dorm
• Gram stain:
• Rust colored sputum
• Polys with gram + lancet shaped cocci in singles and pairs
• CXR:
• Stays within anatomical borders – lobar
• CXR lags behind clinical picture
• Sputum Culture - Usually positive for S.pneumo
• Blood Culture - 20-30% positive
• CBC:
• Leukocytosis
• 15-30,000 WBC
• Left shift common

• History:
• CAP during flu outbreak, post URI, IV drug use, Pleuritic CP
• CXR:
• Patchy infiltrates involving multiple areas of lung
• Gram stain:
• many PMNs & gram + cocci in clusters
• CBC:
• Elevated leukocyte count
• Culture:
• May be positive

• History:
• Smokers/COPD, nursing home
• Children < 2yo
• CXR:
• Broncho/lobar
• Polys and gram - bacilli
• Sputum culture:
• 70 % culture & gram stain pos.
• Blood culture:
• 20-80% blood culture positive

• History:
• Elderly, ETOH/DM/COPD, fever, rigors, sputum +/-blood
• CXR:
• Upper lobe abscess, pleural effusion, +/- interlobar fissure
• Gram stain:
• Polys and gram - rods

• History:
• Common source outbreaks, contaminated water from cooling and ventilation
• CXR:
• dense consolidation
• 50% have pleural effusion
• Gram stain:
• Weakly staining gram negative bacilli
• Fluorescent Ab staining
• CBC:
• Leukocytosis with left shift
• Urine antigen:
• Highly sensitive and specific
• (Hotel across from SUNY Albany)

• History:
• CAP- close quarters, 50% college students, military
• CXR:
• Diffuse patchy infiltrates involving entire lung
• Cold Agglutinins:
• Positive
• CBC:
• Slight leukocytosis
• Gram stain:
• Shows no bacteria
• EIA (Enzyme Immunoassays):
• Serology for diagnosis

done to check for conditions that cause the body to make certain types of antibodies called cold agglutinins. Cold agglutinins are normally made by the immune system in response to infection. They cause red blood cells to clump together (agglutinate) at low temperatures.

• History:
• CAP- flu outbreaks
• CXR:
• Patchy infiltrates, peribronchial thickening, pleural effusion
• Rapid antigen tests can detect influenza, RSV, parainfluenza, and other viruses
• CBC:
• Leukopenia may be notable
• Lymphocytosis common

• Leading cause of mortality from nosocomial infection
• Risk- Obtundation with impaired cough/gag reflex
• Common causes:
• P aerugionsa, Klebsiella, E coli, S pneumoniae, H influenzae 
• Work-up:
• purulent sputum ⇨ culture
• Fever, chills, rigors ⇨ blood culture
• CBC
• CXR
• +/- ABG

• (Acute laryngotracheobronchitis)
• Infection of the upper airways—larynx, trachea, upper levels of the bronchial tree
• Obstruction of airways by edema
• Etiology:
• Parainfluenza viruses (75%), Adenovirus, respiratory syncytial virus (RSV), Mycoplasma pneumoniae (~3–4% of cases)
• Most cases in the autumn and early winter
• Peak age incidence - 3 months to 5 years old
• WBC count -- normal to slightly elevated
• Chest x-ray can be normal, however…
• 40–50% of children, anteroposterior soft-tissue x-rays show subglottic narrowing, -- classic "steeple" sign of croup

• Too numerous to count 
• Lab medicine 
• A popular abbreviation for a 'lawn' of bacteria on a culture plate that may be seen in UTIs - confluent growth is equal to ±105 colonies