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  1. 3 factors if urine composition
    • quantity/composition of plasma presented to kidney
    • renal function (filtration, tubular secretion/absorption)
    • materials added to glomerular fluid from kidneys, ureters, bladder, urethra, and prepuce/vagina/vulva
  2. 4 methods of collection
    • midstream catch
    • catheter
    • cystocentesis
    • manual expression (not recommended, damage or increase RBC)
  3. Minimum urine for UA
  4. Voided sample of urine
    • free catch, midstream preferred.  
    • Preferred method for large animals.  
    • bacteria (genital vs UTI), epithelial cells, spermatozoa, and leukocytes in sample.
  5. Cystocentesis
    • preferred method in small animals and for urine culture. 
    • Danger of iatrogenic hemorrhage and accidental enterocentesis (bowel loop over bladder).  Can also cause increase in RBCs
  6. Catheterized collection of urine
    commonly contaminated by epithelial cells, blood from iatrogenic hemorrhage, lubricant and bacteria
  7. why fresh urine preferred
    • Should be within 30 minutes.  
    • Urea hydrolysis becomes ammonium, increasing pH of urine, which can break down casts or cells.  Oxidation can make in vitro crystals, overgrowth of bacteria can also effect ketones and glucose.  Urine can change color.
  8. Urine storage
    • 3 hours max, refrigerate after 30 minutes.  
    • Can add chemical preservatives
    • warm to room temp before evaluation (redissolve precipitates and enzymes will function properly)
  9. 4 parts of urinalysis
    • visual inspection (color, transparency, odor)
    • chemical analysis (protein, glucose, ketones, etc)
    • specific gravity (refractometer)
    • microscopic sediment (RBC, WBC, bacteria, crystals, casts
  10. Chemical analysis of urine
    • commercially available dipsticks (multistix, chemstrip), at room temp.  
    • semiquantitative eval (+1, +2 etc)
  11. dipsticks test for (10)
    • glucose (changeable, old strips wrong)
    • bilirubin
    • ketones
    • specific gravity (always wrong)
    • blood (not specific, RBC hemoglobin or myoglobin)
    • pH
    • protein
    • urobilinogen (some normal, unstable so false-)
    • Nitrate (false-)
    • leukocytes(must use slide)
  12. Error in dipsticks
    • susceptible to moisture
    • limited shelf life
    • affected by pH of urine or substances
    • reagent pads contaminated (tech fingers)
    • reading at wrong times
    • holding vertically, leakage
    • pigmented urine
    • urine too cold (fridge)
    • color-blindness
  13. Urine Sediment
    • spin low and slow, remove supernatant (specific gravity and chem with supernatant)
    • drop to slide, cover slip.
    • examine at 10x and 40x.  NO OIL FOR URINE
  14. Normal urine output for d/c vs polyuria
    • normal: 20-40ml/kg/day
    • Polyuria: usually not counted until double, so 80ml/kg/day.  Indicates upper UTI.  
    • Be sure not to confuse with pollakiuria, which indicates lower UTI.
  15. Causes of polyuria
    • increased consumption, diuretics, IV fluids or steroids non pathogenic. 
    • Diabetes mellitus (insulin)*
    • diabetes insipidus (aldosterone)
    • Chronic Renal disease*
    • Pyelonephritis
    • pyometra
    • Cushings*dogs
    • liver disease
    • hypercalcemia
    • addisons
    • psychogenic polydipsia
  16. oliguria causes
    • lower water intake, higher temp, hyperventilation nonpathological.  
    • dehydration
    • fever
    • acute renal failure
    • low blood pressure
  17. red or reddish brown urine
    • hematuria
    • hemoglobinuria
    • myoglobinuria
    • Spin sample, RBC will settle so if does not clear, hemo or myo.
  18. dark brown or black urine
    methemoglobinuria.  Tylenol toxicity in cat.
  19. yellow brown to green brown urine
    concentrated sample, bilrubin or pseudomonas
  20. orange urine
  21. normal causes of cloudy urine
    • normal for horse (calcium carbonate crystals and mucus)
    • normal for rabbit (calcium carbonate crystals, appears milky)
    • cats have fat globules
    • standing urine and refrigeration can cause crystallization.
  22. Cloudy urine can have
    • WBC, RBC, epithelium, casts, crystals, mucus, fat, bacteria, sperm
    • contamination from container
    • contamination from feces
  23. Odor of urine
    • can be species and gender dependent (male intact)
    • ammonia odor caused by UTI or urease-producing bacteria
    • sweet or fruity odor caused by ketones.  Diabetes mellitus, ketosis in cows, pregnancy toxemia in ewes and cows.
  24. specific gravity
    • ratio of the weight of urine compared to the weight of water
    • determined by the number and molecular weight of dissolved solutes
    • inversely related to volume (oliguria has high SG, poluria has low SG)
    • reflects renal function
    • measured with refractometer (reagent strips unreliable)
  25. USG of urine depends on
    • eating and drinking habits
    • environmental temperature
    • timing of sample (morning most concentrated)
    • Variable.  Fluctuates throughout the day.
  26. Diabetes mellitus USG
    increase of glucose in urine causes high specific gravity because it's a big molecule, but diabetes causes polyuria
  27. End stage kidney failure urine SG
    same USG regardless of volume of urine
  28. hypersthenuria numbers
    • > 1.030 for a dog
    • > 1.035 for cats
    • > 1.025 for horse/cow
    • Filtrate has been concentrated by renal processes
  29. hyposthenuria numbers
    • < 1.008
    • filtrate has been diluted by renal processes (working)
  30. isosthenuria numbers
    • 1.008-1.012
    • USG approaches that of glomerular filtrate
    • neither concentrated nor diluted by renal processes
  31. pathological and nonpathological causes of USG hypersthenuria
    • nonpathological: decreased water intake, increased fluid loss (sweat, panting, VD), increased excretion of urine solutes (high environmental temp or hyperventilation)
    • Pathological: dehydration, fever, diabetes mellitus, protein, glucose or cells in urine
  32. pathologial and nonpathological causes of hyposthenuria
    • nonpathological: excess water consumption, diuretics, IV fluids, steriods (exogenous or endogenous)
    • Pathological: diabetes insipidus (kidneys don't respond to ADH), pyometra, psychogenic polydipsea, cushings
  33. pathological and nonpathological causes of isostenuria
    • persistent isosthenuria indicates primary renal disease (single sample nondiagnostic)
    • Isosthenuric urine + dehydration + azotemia = renal disease
  34. pH
    • measured with reagent strips or pH meter
    • 7 = neutral
    • >7 = alkaline
    • < 7 = acidic
    • Depends on species, stress,  and diet
  35. diet and pH
    • plant material causes alkaline urine (herbavores)
    • meats and dairy cause acidic urine (carnivores)
    • Omnivores depend on what they ate
  36. pH of stress/excitment
    usually increases (alkaline), especially cats.
  37. Normal pH of urine of cat, dog, horse, cow
    • Dog: 6-7
    • Cat: 6-7 (usu lower than dog)
    • horse: 7-8.5
    • cattle: 7-8.5
  38. Causes of alkaline urine
    • veggie based diet
    • UTI (urease + organisms)
    • administration of alkaline agents
    • metabolic/respiratory alkalosis
    • postprandial (alkaline tide, response when H+ all goes into stomach)
    • distal renal tubular acidosis
    • urine allowed to stand open at room temp (CO2 lost , blows off
  39. Causes of acidic urine
    • meat-based diet
    • administration of acification units
    • metabolic or respiratory acidosis
    • hypokalemia
    • chloride depletion
    • protein catabolism
  40. Reagent strip protein
    • dilute urine causes false neg. 
    • changes in color pad to correspond to expected,  raped, convenient, reasonable accurate
    • abnormal urine color may interfere
    • alkaline urine causes false positives (protein)
    • Primrily detects albumin
  41. SSA turbidity in protein
    • Sulfosalicylic acid
    • sensitive to albumin and GLOBULIN (better than strip)
    • proteins are denatured by acids, form a precipitate which increases turbidity.  
    • Turbidity proportional to protein
    • Semiqualitative (+1, +2, etc.)
  42. Protein:Creatinine ratio
    • qualitative, confirms proteinuria, sign of renal before 75% loss/azotemia.
    • Not affected by concentration or volume (low USG=false on strip)
    • Healthy dog <0.2
    • renal >0.5
    • questionable in between
  43. physiologic (nonpathogenic) proteinuria
    • circumstantial, often transient
    • renal vasoconstriction, ischemia, congestion
    • excessive protein intake
    • strenuous exercise
    • seizures
    • fever
    • temperature extremes
    • stress
  44. Prerenal pathological proteinuria
    • increased plasma concentration of small proteins that pass through glomerulus (excess, some absorbed in glomerulus)
    • young neonates, w/in 24-40 hours
    • Bence-Jones proteins (paraproteins, multiple myeloma)
    • hemoglobin (Intravascular hemolysis)
    • myoglobin (severe muscle injury, rhabdomyolysis)
  45. glomerular renal proteinuria
    • from glomerular disease, damaging filtration barrier, usually albumin leaking
    • decreases selectivity, increased permeability to large or negative plasma proteins, incomplete resorption
    • Glomerulonephritis (UPC 3-5), amyloidosis (UPC ~15)
    • Frequently both tubular and glomerular problem together
  46. glomerularnephritis
    chronic inflammation which eventually destroys nephron
  47. Disorders causing glomerular proteinuria
    • immune-mediated
    • infectious (often tick-borne)
    • diabetes mellitus
    • pituitary dependant hypoadrenocorticism (PDH)
    • Hypertension
    • hereditary forms
    • inflammatory
    • amyloidosis
  48. tubular renal proteinurias
    • defective proximal renal tubule not resorbing normal proteins.  Usually mild, leaking globulin protein.  
    • Toxicosis (ethylene glycol, aminoglycosides, lead)
    • Hypoxia
    • congenital
    • Frequently both tubular and glomerular problem together
  49. urogenital proteinuria
    • hemorrhage or inflammation
    • Cystitis
    • Prostatitis
    • urethritis (female more than male)
    • vaginitis
    • Trauma (secondary to cystocentesis, catheterization or bladder expression)
  50. Proteinuria false positive causes
    Proteinuria false negative causes
    • Positive: alkaline urine, disinfectants, pigmented urine, concentrated urine
    • Negative: dilute urine, acidic urine
  51. glucosuria
    • usually negative unless blood glucose level exceeds renal threshold (rates of glomerular filtration and tubular reabsorption, 170-180 mg/dL)
    • IV Dextrose
    • excessive glucocorticoids (STRESS in cats)
  52. causes of glucoseuria
    • Physiologic hyperglycemia: stress, postprandial, excitement/fright, diestrus
    • Pathologic hyperglycemia: diabetes mellitus, pancreatitis, cushings, hyperthyroid
    • Renal glucosuria: damaged/abnormal proximal tubule (fanconi syndrome acquired or congenital) previous stress or excitement
  53. Glucoseuria false negatives or positives
    • False positives: hydrogen peroxide or bleach
    • False negatives: ascorbic acid, high ketones (diabetic ketoacidosis), cold urine, expired reagent strips, formalin vapors
  54. Ketogenesis
    excessive fat catabolism
  55. ketosis
    pathologic state caused by excess ketogenesis
  56. ketoacidosis
    ketosis with acidosis
  57. ketonuria
    • excessive ketones in urine caused by burning too much fat.  
    • undetectable normally.  False negatives common due to B-hydroxybutyric acid (use ACE test)
  58. what can screw up all results?
    pigmented urine
  59. ACE test
    measures all types of ketones, including B-hydroxybutyric acid, which dipsticks don't pick up
  60. ketonuria false positives and false negatives
    • false positives: pigmented urine
    • false negatives: old urine (30 minutes or 3 hours refrigerated)
  61. Causes of ketonuria
    • diabetes mellitus
    • starvation (maldigestion/malabsorption, prolonged VD)
    • high fat, low carb diet (atkins)
    • hypoglycemic disorders (pregnancy disease in ewes and ketosis in cows)
  62. Bilirubin
    • breakdown product of hemoglobin, conjugated or unconjugated
    • Conjugated: conj in hepatocytes, to bile and back into circ, filtered by glomerulus, not resorbed by tubules
    • Unconjugated: rare to see, bound to albumin so too big to get into tubules
  63. Bilirubinuria
    • dog can be +1 safely.  
    • From bilirubinemia (hemolysis, biliary disease, hepatic disease, pre-and post)
  64. Pre-hepatic pathologic bilirubinuria
    • hemolytic diseases (seen on HCT, regenerative anemia) like IMHA, or infectious like RBC parasites (mycoplasma haemofelis, babesia canis or gibsoni)
    • metabolic like heinz body anemia (propylene glycol in cats, onions)
    • Traumatic (microangiopathic disease, schistocytes)
  65. hepatic pathologic bilirubinuria
    • hepatocellular disease: 
    • infectious (viral hepatitis, Leptospirosis)
    • cirrhosis
    • chronic active hepatitis
    • neoplasia of liver
    • toxins
  66. Posthepatic pathologic bilirubinuria
    • Cholestasis, could be choleliths or colecystitis.
    • Could be anywhere along biliary, often presents with hepatitis (backs up into liver)
    • cholangiohepatitis, mucoseal
  67. Positive for occult blood on reagent strip can be
    • RBCs
    • free hemoglobin
    • free myoglobin
  68. hematuria mechanism
    RBCs lyse on contact with the reagent pad, causing positive reaction.  Lyse required.
  69. Clinical causes/appearance/microscope of hematuria
    • bleeding into urinary tract: inflammation, trauma, neoplasia, calculi, coagulopathy
    • Looks red, 2-3 RBCs/hpf.  Spin, RBC will sink
    • RBCs lyse when stored too long, too dilute or alkaline.
  70. hemoglobinuria and clinical causes/appearance/microscope
    • Free Hb in urine from hemoglobinemia (won't clear when spun).
    • Causes: intravascular hemolysis, toxicity, mechanical damage, infectious damage
    • appearance: port wine color to urine
    • microscope: lack of RBC, doesn't clear with centrifuge
  71. myoglobinuria
    • Mb in urine as a result of being in blood,
    • caused by: excess muscle breakdown, muscle disease or trauma (myocyte injury releases myoglobin)
    • filtered by glomerulus
    • appearance: dark brown or black
    • lab: elevated CK, AST
  72. sedimentation and what you need/do
    • 5mL
    • centrifuge at low speed
    • remover supernatant, drop on slide and examine stained and unstained
    • ideally analyze within an hour of collection
  73. normal urine sediment
    • not much in domestic animals, includes epithelial cells, mucus, RBCs, WBCs, casts and crystals
    • Horses and Rabbits have calcium carbonate crystals, causing cloudy/milky urine
  74. Pyuria
    • increased WBCs in urine
    • looks cloudy.  
    • >5/hpf (less is normal)
    • Caused by UT inflammation (infection or not), genital catch inflammation (voided sample) or contamination (voided)
  75. WBCs in sediment
    • spherical, dull gray or greenish-yellow, granules, lobulated nucleus
    • Most are neutrophils
    • shrink in concentrated, swell in dilute
    • larger than erythrocytes, smaller than renal epithelial cells
  76. Epithelial cells
    • makes urine cloudy
    • small amt normal (shedding and replacing), lots means inflammation
    • squamous, transitional, or renal
  77. Squamous epithelial cells
    • lower urethra and genital tract, mostly only from voided samples.  
    • Flat, thin, fried-egg, homogenous cells
    • largest cells in sediment
  78. transitional epithelial cells
    • bladder, ureters, renal pelvis and proximal urethra
    • normal in small amounts
    • increased from cystitis, pyelonephritis, and catheterization
    • Transitional Cell Carcinoma in Westies
  79. Renal epithelial cells
    • from renal tubules, very rare (0-1/hpf), increased numbers suggest disease of kidney parenchyma
    • smallest epithelial cell, spindle-shaped, round, large nucleus and no to fine granules
  80. neoplastic epithelial cells
    • not normal, from tumor usually
    • Different sizes, mitotic, basophilic, ropy chromatin pattern
    • most common is Transitional Cell Carcinoma in the bladder in Westies
  81. Casts
    • tubular structures from renal tubules made of protein from plasma, mucoprotein from tubules and cells.  
    • Classified by appearance
    • hyaline or fine granular 0-3/hpf normal, esp after physical activity
    • Most significant in dilute urine
    • Lots suggest renal lesion in tubules
  82. Types of casts (transformation) and what decides
    • which cast develops depends on how quickly filtrate is moving and how much damage.  
    • hyaline > epithelial (cellular) > coarse granular > fine granular > waxy
    • Usually formed more distally where urine is more acidic
  83. Casts and renal disease
    • can be disease without casts, particularly in chronic, progressive or generalized nephritis
    • shed intermittantly
    • unstable in urine, dissolve in time, esp in dilute or alkaline urine (like in renal disease)
    • Not reliable for diagnosis
    • Regeneration is possible if basement membrane undamaged
  84. Hyaline casts
    • composed of protein only
    • clear, colorless, transparent, easier to see in stain or low light
    • 0-3/hpf normal
    • Caused pathologically by: renal or extra-renal proteinuria, chronic kidney disease, fever, dehydration, strenuous exercise or general anesthesia
  85. Cellular cast
    • degeneration and necrosis of tubular epithelial cells due to acute tubular injury (ischemia, infarction, nephrotoxicity like grapes)
    • Made of RBC, WBC, epithelial cells
    • does not tell extent or reversibility of disease
  86. epithelial casts
    • renal epithelial cells embedded in hyaline matrix
    • acute nephritis, ischemia, infarction, toxins
  87. granular casts
    • Hyaline cast (coarse or fine) containing granules from tubular epithelial cells, RBCs and WBCs (cells go into cast then are degraded)
    • a few normal, increased due to acute nephritis (more severe than hyaline)
    • reflect degeneration/necrosis/inflammation of tubules
  88. waxy casts
    • ALWAYS pathologically significant (not diagnostic)
    • chronic or severe tubular degeneration.  
    • Like hyaline but square ends, wider, dull, homogenous, waxy appearance, colorless or gray. Look like ziti
  89. Fatty casts
    • full of refractile fatty droplets (drops common in cats) in a hyaline or granular background.  
    • seen in cats with renal disease and dogs with diabetes mellitus.
    • lots suggests degeneration of tubules
  90. Bacteria in sediment
    • caused by UTI, genital tract infection, invitro growth or contamination.
    • normal urine is sterile, some may be in free catch normally
    • reported as few, moderate, many, TNTC
    • Often seen with increased WBC and RBC (UTI)
    • Use cysto for accuracy, then culture and sensitivity
  91. Common bacteria in UTI and how to ID for sure
    • E. coli bacilli common (anal contamination).  
    • Gram stain to be sure of bacteria
    • Neutrophil/macrophage can be eating bacteria
  92. yeast and fungi
    usually contaminants, could indicate fungal UTI in long-term abx users.
  93. Parasites
    • Ova visible in sediment.  
    • Capillaria plica most common, capillaria felis-cati and dioctophyma renale
    • Could also be fecal contamination (roundworms)
    • heartworms.
  94. Mucus threads
    • confused with casts but don't have delineated edges
    • lots in equine
    • Otherwise urethral irritation or contamination from genital secretions
  95. Sperm
    • occasionally seen in intact males or bred females
    • no clinical significance
    • may cause protein positive
  96. Lipuria
    • fat droplets in urine
    • lightly green, highly refractile, spherical bodies of varying sizes (unlike yeast and RBC)
    • some in most cats
    • caused by: obesity, diabetes mellitus, hypothyroidism and high-fat meal
  97. crystalluria
    • may or may not be significant (cold, age), some normal
    • Caused by metabolic diseases (shunts cause calcium oxalate)
    • type depends on pH, concentration, temperature, solubility
    • Occasional, moderate or many (+1 - +4)
  98. crystals that form in alkaline urine
    • Triple Phosphate
    • Amorphous Phosphate
    • Calcium Carbonate
  99. Crystals that form in acidic urine
    • Everything not alkaline
    • ammonium biurate
    • amorphous urate
    • calcium oxalate
    • cholesterol
    • cystine
    • bilirubin
    • uric acid
    • tyrosine
  100. struvite crystals
    • triple phosphate, common in d/c with alkaline urine (>/=7)
    • Can be caused by urease-producing bacteria UTI
    • 3-6 sided prisms, "coffin lids"
    • most common
  101. amorphous phosphate crystals
    granular precipitates in alkaline urine.
  102. Calcium carbonate crystals
    • no clinical significance, appear in alkaline urine and very common in horses and rabbits.  
    • Dumbell shape or spherical with radiating spokes (pinwheel or diamond)
  103. Ammonium biurate crystals
    • acidic urine, seen in healthy (esp dalmations and EBD)
    • liver dysfunction, PSS in dog/cat
    • brown spheres with long irregular spicules, "thorn apple"
  104. amorphous urate
    acidic urine, yellow-red granular precipitates.  Small numbers normal, large numbers mean faulty uric acid metabolism (Dalmations), portovascular malformation, severe hepatic disease, ammonium urate urolithiasis
  105. Calcium oxalate dihydrate
    • acidic urine, common in male dogs, stones.
    • Small squares with X, fortune-teller.  
    • Normal in rabbits, horses, dogs and cats
    • caused by: abnormal calcium excretion, ingestion of O2-rich plants, ethylene glycol toxicity (usually mono).
    • Large numbers form calculi
  106. calcium oxalate monohydrate
    • small and dumbell shaped or elongated and pointed at each end (Picket fence)
    • ethylene glycol toxicity
    • hypercalcemia (hyperparathyroidism)
  107. Hippuric acid crystals
    • very rare, often confused with calcium oxalate monohydrate crystals
    • normally found in horses/herbivores
    • acidic, neutral or slightly alkaline urine
  108. cholesterol crystals
    • acidic.  Uncommon.  
    • Parallellogram with notched corner (broken plate)
    • seen in healthy dogs
    • hyperhcolesterolemia and proteinuria (protein-losing nephropathy
  109. cystine crystals
    • acidic urine, rare.  
    • Flat, hexagonal, colorless, thin, stop-signs
    • renal tubular dysfunction (amino acids not resorbed in proximal tubules)
    • Cystine urolithiasis seen in dachshunds, newfoundlands, EBD, scottish terriers
  110. uric acid crystals
    • colorless, flat and diamond-shaped or 6-sided.
    • Seen in dalmations and EBD, almost never otherwise.  
    • Large numbers could mean liver dysfunction, PSS, faulty uric acid metabolism, portovascular malformation
  111. bilirubin crystals
    • yellow to amber pile of twigs or antlers (pick-up sticks)
    • low numbers in highly concentrated canine urine. 
    • Otherwise caused by bilirubinemia (prehepatic, hepatic, posthepatic)
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Urinalysis in Clinical Pathology Lecture
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