Urinalysis & Hematology Flashcards
Urine Preservation
- Centrifuge immediately for microscopic evaluation
- Can refrigerate for 2-12 hours, but bring to room temp before testing
- Freezing can be done for chemistry but will destroy cells
Continence
Storing of urine in the bladder as it fills
Oliguria
Decrease in urine
Pollakiuria
Frequent urination
Polyuria
Urinating large volumes
Urine Transparency
Exceptions
Generally will be clear, but exceptions include
* horses: calcium carbonate crystals and mucus present
* rabbit / hamster / guinea pig: calcium salts present
* cats: fat present
* cattle: calcium carbonate crystals will form in older urine
USG
Urine Specific Gravity
* assesses how well renal tubules concentrate / dilute filtrates from glomerulus
* how well kidneys maintain water and osmotic pressure
* will decrease as temp increased
Isosthenuria
- “Fixed SG”
- 1.008 - 1.012
- neither diluted or concentrated
- same glomerular filtrate as plasma
Hyposthenuria
- SG < 1.008
- urine diluted below SG of plasma
Hypersthenuria
- SG > 1.012
- Urine concentrated more than SG of plasma
Urine pH
Body’s acid-base balance
* acidic = pH <7
* alkaline = pH >7
Urine pH
Affects of Diet
- Herbivores: alkaline (unless nursing)
- Carnivores: acidic
- Omnivores: can be either
- General: less acidic after meals (alkaline tide)
Urine pH
Open / Standing
Leads to false increases in pH
* loss of CO2
* bacteria quickly multiply
Urine Protein
- Normal: none or trace
- Indicator for renal disease, especially if casts seen
Urine Protein
False Readings
False-Positive
* alkaline / highly concentrated urine
* strip left in urine too long
False-Negative
* globulins causing increased protein
UPC
Urine Protein-to-Creatinine Ratio
* confirm proteinuria
* lower level of detection
Urine Glucose
Depend on glucose levels in blood
* normal: none
* occurs when renal threshold reached
Urine Glucose
False-Positives
- Fear
- Stress
- Excitement
- Recommend to fast prior to test
- Certain drugs
Urine Ketones
Produced during fat metabolism
* important source of energy
* very small amount found in blood
* excess metabolism will cause ketones to spill into urine
Urine Ketones
Increased
Excess Ketones are toxic
* CNS depression
* acidosis
Urine Ketones
and Glucose
Ketosis associated with hypoglycemia
* high glucose demands
* pregnancy and diabetes-associated diseases
Urine
Urobilinogen
Small amount in urine from breakdown of bilirubin
* majority eliminated in feces
Urine
Bilirubin
- Only conjugated found in urine
- Rough determination done by shaking urine and looking for yellow foam
Urine Bilirubin
False Results
- Positives reliable in cats, but not dogs
- False negatives: light will oxidize
Urine
Blood
When present
* evaluate blood serum or plasma
* evaluate urine supernatant
Urine
Hematuria
Associated with disease of urogenital tract
* supernatant cloudy (pre-centrifuge)
* supernatant colorless (post-centrifuge)
Urine
Hemoglobinuria
Indicates intravascular hemolysis
* urine and plasma / serum will be reddish
Urine
Myoglobinuria
Indicates pathological condition of muscle or overexertion
* blood plasma will be colorless
* spun urine supernatant will be reddish
Urine WBC
False Readings
- Cats = false-positives
- Dogs = false-negatives
- False-negatives = increased glucose and USG
- False-positives = old urine
Urine
WBC
Most WBCs in urine are Neutrophils
* larger than RBCs
* smaller than epithelial cells
Urine
Epithelial Cells
- Squamous
- Transitional
- Renal
Urine Cell
Squamous Epithelial Cell
* largest cells in urine
* come from urethra, vagina, and vulva
* irregular-shapped
* partially or fully cornified
* small round nuclei may be present
* not significant finding
Urine Cell
Transitional Epithelial Cells
* come from bladder, ureters, renal pelvis, urethra
* variation in size and shape
* may be increased with catheterization
* see with inflammation or neoplasia
Urine Cell
Renal Epithelial Cell
* come from renal tubules
* slightly larger than WBCs - can be difficult to distinguish from
* round with large nucleus
Urine
Casts
Formed by and take the cylindrical shape of kidney tubules
* acidic environments
* presence of protein
* increased flow time through tubules
* increased salt concentration
Urine Cast
Degradation Order
- Hyaline
- Tubular / Cellular
- Coarse Granular
- Fine Granular
- Waxy
Urine Cast
Hyaline Cast
* clear / colorless
* composed of protein
* rounded ends
* mimick mucus strands
* few seen can be normal
* mildest form of renal irritation
Urine Cast
Cellular Cast
* contain cells from renal epithelium
* usually always significant
Urine Cast
Granular Casts
* most common
* coarse vs fine
Urine Cast
Waxy Cast
* wide with square ends
* “brittle” appearance
Urine Crystal
Struvite
* triple phosphate: magniesium ammonium phosphate
* “coffin lids”
* form in alkaline urine
* associated with bacteria
Urine Crystal
Amorphous Phosphate / Urate
* phosphates: colorless and granular; found in alkaline urine
* urates: brown color; found in acidic urine