Urinalysis and Body Fluids

Card Set Information

Urinalysis and Body Fluids
2013-05-03 01:19:06
Urine Chemical Examination

Urine Chemical Examination
Show Answers:

  1. What is the normal color of urine derived from?
  2. What forms from the oxidation of urobilinogen as urine stands and adds minimally to the normal yellow color?
  3. What adds a slight pink pigment (usually following refrigeration), when the pigment attaches to precipitated amorphous urates?
  4. What does a pale yellow urine generally indicate?
    • Dilute
    • Diabetes insipidus or diabetes mellitus with increased urine excretion
  5. What does a dark yellow urine generally indicate?
    • Concentrated specimen (first morning or strenuous exercise)
    • Dehydration
  6. What does a intense yellow/amber/orange urine generally indicate?
    • Pyridium: (phenazopyridine) meds prescribed for UTIs
    • Bilirubin: bilirubinemia occurs with liver problems, hepatitis, biliary obstruction
  7. What does a yellow foam on a urine generally indicate?
    Forms when urine is shaken due to the presence of conjugated bilirubin
  8. What does a red/pink urine generally indicate?
    • Blood
    • Hemoglobin, erythrocytes
    • Myoglobin (muscle trauma)
    • Prophyrins
  9. What does a green/blue generally indicate?
    • Meds and dyes such as amitriptyline, indican, phenols
    • Infections caused by Pseudomonas species
  10. What does a pale brown/black generally indicate?
    • Glomerular bleeding
    • Denatured hemoglobin, melanin, or homogentisic acid
  11. What does the sweet or fruity odor of urine indicate?
    Ketone bodies (diabetic ketosis)
  12. What does the maple syrup odor of urine indicate?
    Maple syrup disease
  13. What is the first renal function to become impaired?
  14. How does the refractometer work?
    Measure a refractive index by comparing the velocity of light in air to the velocity of light in a solution
  15. What is the normal range of specific gravity?
  16. What is the term for urines with <1.010 SG?
    Hyposthenuric urine
  17. What is the term for urines with >1.010 SG?
    Hypersthenuic urine
  18. What conditions does a low specific gravity indicate?
    • Loss of the kidney's ability to concentrate urine 
    • Presence of disease (diabetes insipidus, glomerulonephritis, pyelonephritis)
  19. What conditions does a high specific gravity indicate?
    • Adrenal insufficiency
    • Diabetes mellitus
    • Hepatic disease
    • CHF
    • Dehydration
    • Interference from X-ray contrast media
  20. How is pH regulated in the body?
    • Primarily regulated by the lungs and kidneys
    • Kidneys provide regulation through secretion of hydrogen ions via ammonium ions, hydrogen phosphate, and organic weak acids
    • Kidneys also facilitate reabsorption of bicarbonate from the convoluted tubules
  21. What do acidic pH's in urines indicate?
    • High protein diets
    • After normal sleep
    • Respiratory/metabolic acidosis
    • Uncontrolled diabetes mellitus
  22. What does an alkaline pH in urine indicate?
    • Excreted in urine after in response to gastric HCl
    • Vomiting
    • Increased consumption of veges
    • Renal tubular acidosis
    • Respiratory/metabolic alkalosis
    • UTIs
  23. What indicators are used on the reagent strip?
    • Methyl red
    • Bromthymol blue
  24. What indicator is used on the reagent strip to detect protein?
    Tetrabromphenol blue
  25. What is the normal range for protein in a random and 24 hr urine?
    • Random: <10 mg/dL
    • 24 hr: 100 mg/24 hr
  26. What can urine protein indicate?
    • Renal disease
    • Tubular reabsorption problems
    • Increased low molecular weight proteins
    • Glomerular membrane damage caused by toxic agebts , lupus, or streptococcal glomerularnephritis
    • Multiple Myeloma
  27. What is a key indicator of Multiple Myeloma?
    Bence Jones protein in the urine
  28. What is:
    Produced due to a proliferative disorder of plasma cells as seen in Multiple Myeloma
    Proteins are light chain monoclonal immunoglobulins
    Bence Jones protein
  29. What condition can occur in cold temps and as a result of exercise, fever, dehydration, late pregnancy, and orthostatic/postural proteinuria in young adults
    Benign proteinuria
  30. What is a useful evaluation for patients with renal complications of diabetes mellitus and what are abnormal results?
    • Microalbumin
    • 30-299 mg albumin/g creatinine
  31. What test is:
    Performed only for comparison with protein level to rule out microalbuminuria
    Provides an assurance that the water volume of the sample is NOT influencing the protein concentration
  32. How will you get a false positive and false negative for creatinine?
    • False positive: None
    • False negative: Ascorbic acid
  33. What test is most commonly used to detect diabetes mellitus?
  34. What is present in:
    Diabetes mellitus
    Impaired tubular reabsorption seen in Fanconi syndrome
    Advanced tubular renal disease
    CNS damage
    Thyroid disorders
  35. What is the enzyme used to detect glucose on reagent strips?
    Glucose oxidase
  36. What gives false positives and false negatives for glucose on the reagent strip?
    • False positive: Antibiotics, Ascorbic acid and other reducing agents
    • False negative: NONE
  37. How does the Copper reduction test work?
    Glucose reduces copper sulfate to cuprous oxide
  38. What are included in ketones?
    • 3 Intermediate products of fatty acid metabolism:
    • Acetone
    • Acetoacetic acid
    • Beta-hydroxybutyric acid
  39. What is the clinical significance of ketones in urine?
    • Uncontrolled diabetes mellitus
    • Insulin dosage monitoring
    • Electrolyte imbalance
    • Dehydration due to excessive carb loss such as vomiting, starvation, exercise, and rapid weight loss
  40. What indicator is used in the reagent strips to detect ketones and how?
    • Sodium nitroprusside is used to measure acetoacetic acid
    • The addition of glycine permits the measurement of acetone and acetoacetic acid
  41. What test:
    Is a nitroprusside and glycine tablet used to detect ketones
    Gives an enhanced color reaction
    Permits serial dilutions to be done
  42. What method uses beta-hydroxybutyrate dehydrogenase to detect the presence of beta-hydroxybutyric acid?
    Enzymatic method
  43. What types of blood are in a urine?
    • Hematuria (intact RBCs)
    • Hemoglobinuria (Hgb in the urine)
    • Myoglobin (Hgb-like protein found in muscle tissue
  44. How do you screen for myoglobin in urine?
    • Use ammonium sulfate to precipitate Hgb out of the urine
    • The urine supernatant is then filtered and tested with a reagent strip
    • Positive is myoglobin
  45. What will give you false positive and false negative results with a reagent strip with blood?
    • False positive: Vegetable peroxidase and E. coli peroxidase
    • False negatives: High levels of ascorbic acid or nitrites, formalin preservatives, captopril (hypertension meds)
  46. How is bilirubin produced?
    • Hgb is metabolized into iron, protein, and protoporphyrin
    • Protoporphyrin is converted to bilirubin by the reticuloendothelial system cells
    • Bilirubin binds to albumin for transport to the liver as unconjugated bilirubin
  47. What clinical conditions cause bilirubinuria?
    • Hepatitis
    • Cirrhosis
    • Biliary obstruction
    • Early liver disease when conjugated bilirubin enters the circulation
  48. What is the water soluble form of bilirubin and excreted in the urine?
    Conjugated bilirubin
  49. How is conjugated bilirubin removed from the body?
    Excreted in the urine
  50. What form of bilirubin is NOT water soluble and cannot be excreted in urine?
    Unconjuated bilirubin
  51. How is unconjugated bilirubin removed from the body?
    • Bilirubin binds to albumin for transport to the liver as unconjugated bilirubin
    • In the liver, bilirubin is conjugated with glucuronic acid to form bilirubin diglucuronide
    • Bilirubin diglucuronide goes into the intestines and is reduced to urobilinogen via bacterial action and excreted in the feces as urobilin
  52. What condition is indicated when urine:
    Bilirubin POS
    Urobilinogen NORMAL
    Bile duct obstruction
  53. What condition is indicated when urine:
    Bilirubin NEG
    Urobilinogen POS
    • Hemolytic disease
    • (Unconjugated form increases in the plasma)
  54. What reaction is used to detect bilirubin in the urine?
    Diazonium salt
  55. What tablet is used to confirm a reagent strip bilirubin?
  56. What causes a false positives and false negatives for bilirubin?
    • False positives: pigmented urine
    • False negatives: specimen is too old, excessive exposure to light, ascorbic acid, and nitrite
  57. What product is:
    Formed from Hgb metabolism
    Produced from the reduction of bilirubin by bacteria in the small intestine
  58. What conditions cause an increased urobilinogen?
    • Early liver disease
    • Hepatitis
    • Hemolytic anemias
  59. What reagent is used to detect urobilinogen in a reagent strip?
    • Ehrlich's reagent or
    • Diazo dye
  60. What gives false positives and false negatives for urobilinogen on a reagent strip?
    • False positive: Pigmented urine
    • False negative: Improper storage, high levels of nitrite
  61. What is a rapid test for UTIs on a reagent strip?
  62. What conditions does a positive Nitrite indicate?
    • Cystitis (bladder infection)
    • Pyelonephritis
  63. What can give false positives and false negatives for nitrite in a reagent strip?
    • False positives: standing urine, pigmented urine
    • False negatives: Ascorbic acid, antibiotics, bacteria that do not reduce nitrate, inadequate time in the bladder, heavy concentration of bacteria
  64. What conditions does a positive leukocyte esterase indicate?
    • UTI
    • Infammation of the urinary tract
  65. What gives false positives and false negatives for leukocyte esterase on the reagent strip?
    • False positives: pigmented urine, strong oxidizing agents
    • False negatives: Increased glucose, protein, ascorbic acid, lymphocytes, high specific gravity
  66. What can high levels of ascorbic acid (Vit C) do to a urinalysis reagent strip?
    • False positive: Glucose
    • False negatives: Creatinine, Blood, Bilirubin, Nitrite, Leukocyte esterase
  67. What test is used  to monitor hydration and dehydration, loss of renal tubular concentrating ability, and diabetes insipidus?
    Specific gravity
  68. What causes false positives and false negatives for a specific gravity on a reagent strip?
    • False positive: Increased protein or ketones
    • False negatives: If urine pH is >6.5 then add 0.005 to the reading