Intro to Urinalysis (chem lect 3, 4) Flashcards
MDB (Minimum Database)
- CBC
- Serum biohemistry
- UA
To evaluate hydration you need a …….
Spec grav (specific gravity)
These can’t be assessed without knowing hydration status
Relative Erythrocytosis
Relative Hyperproteinemia
Indications for Urinalysis
- Clinical or biochemical evidence of urinary tract disease
- Dehydration
- Urine spec grav must be documented prior to fluid therapy to properly assess kidney function in dehydrated patients - Evidence of hemolytic disease
- Search for diagnostic crystalluria
- Liver dz
- Antifreeze (ethylene glycol poisoning)
- Drug therapy - Search for organisms in systemically infected animals
- Bacterial discospondylitis
- Systemic aspergellosis
Before giving fluids must…
Get a spec grav
Cholistasis
Back up of bile in the liver
Marker for intravascular hemolysis
Hemaglobinemia (happens before build up in urine)
- Liver disease causes….. in urine
- Ethylene glycol poisoning
- Sulfa drugs (TMS)
- Aspergillosis
- Ammonium biurate crystals
- portosystemic shunt - Calcium oxolate monohydrate crystals (only in the 3-18 hours after ingestion)
- Sulfa crystals in urine
- Bacteria secreted in urine
Time of Day for Sample collection of urine
AM
AM (Fasting)
- higher USG (dec/no water intake)
- lower pH
- more formed elements (if longer period of formation)
Jen wants this to be able to evaluate concentrating ability
Time of day for sample collection
PM
PM (non fasting)
- lower USG
- more alkaline pH
- possibly fewer formed elements
- if shorter period of formation
When looking at Urine or liquid samples ……..the condenser
Drop down
You want it to be a little dark
Urinalysis Procedure
- Evaluation of urine sediment
- Should be performed within 1 hour after collection
- Refrigeration allows prolonged storage prior to analysis
- ideally within 12 hours
- After 24 hours cells begin to lyse
- Artifacts:
- increased urine pH
- microbial proliferation
- degradation of cells and casts
- degradation of bilirubin and ketones
- Cold can falsely inc specific gravity (denser)
- Allow to warm to room temp before analysis
3 ways to obtain urine
- Cystocentesis (enterocentesis)
- Transurethral catheterization
- Voided sample
- Emergency retrieval
- From floor or table (dipstick for oxidation and glucose will be innacurate)
- Never culture this
Fanconi Syndrome
- Disease of proximal renal tubules of kidney
- Things pass into urine instead of being reabsorbed
- Glucose
- Amino acids
- Uric acid
- Phosphate
- Bicarbonate
- Indication of infection in urine.
- What inhibits this …
- Neutraphils
- Cushings - causes PUPD
or
chem
Cystocentesis
and contraindications
- Preferred method for small animals
- Avoids lower urinary tract contaminants (south of bladder)
- Contraindications
- clotting disorders
- thrombocytopenia
- Ideally collect 5-6 mL for analysis
Technique after collection
- Spin down urine
- pull off liquid
- add back 1 mL and resuspend pellet (in 20 percent of volume)
Sample Processing of urine
- Save 1 ml of unspun urine for chem analysis
- Do the pellet thing
- Prepare stained and unstained slide preps
- staining can introduce artifact, unstained better
- staining IS necessary if you suspect tumor cells
Gross inspection
Use unspun urine for
- Color
- Clarity
Make sure container is sealed
-Ketones can evaporate (important for diabetic patients)
Urine Color
- Can’t reliably asses concentration by color
- pigments in food
Hemoglobin vs RBCs in Urine
If spun, RBCs pellet to the bottom of the tube.
Hemoglobin stays in soln
Myglobin seen in ……
then do….
Muscle necrosis (horse tying up)
then do
AST and CK
*rarely seen in dogs
Urine colors
- Light to medium yellow
- Colorless
- Very dark yellow
- Red to brownish-red
- Reddish-brown to brown
- Greenish tint
- Light to medium yellow
- normal - Colorless
- very dilute - Very dark yellow
- very concentration
- bilirubinuria - Red to brownish-red
- hematuria
- hemoglobinuria
- myoglobinuria - Reddish-brown to brown
- myoglobinuria
- hemoglobinuria
- methemoglobin - Greenish tint
- bilirubinuria
Methemoglobinemai => Hersey syrup blood
Oxidative damage
- aspirin / acetaminophen ingestion
- red maple toxicity in a horse
Blood smear
- Heinz bodies
- eccentracytes
- possible anemia
- methemoglobinuria
Factors affecting pH of Urine
- Carnivores and suckling herbivores: 5.5 - 7.5
- Herbivores: 7.0 - 8.5
- H+ excreted & HCO3- absorbed
- Age of urine: loss of CO2 to air raises urine pH
- Presence of contamination or pathogenic bacteria
- Urease positive bacteria: convert urea to ammonia / ammonium ion (inc. pH)
- Streptococcus
- Ureaplasma
- Proteus spp.
Postprandial alkaline tide
Inc secretion of HCl into stomach for digestion
-H sequestered in stomach making the rest of the body more alkalotic
Glucose
- interpret in light of blood glucose level
- Cats have higher renal threshold for glucose
- stress-induced transient hyperglycemia in cats
- stressed cats are insulin resistent
- stressed cats up to 250 mg/dL glucose may not be big deal
- False negatives possible with vitamin C administration
* it’s an anti-oxidant…but why it makes glucose neg. don’t know
Ketones
- Small organic acids
* when you break down fatty acids instead of carbohydrates - Most dipsticks DON’T detect primary ketone produced by veterinary species
* B-hydroxybutyrates - Most dipsticks DO detect acetone and acetoacetic acid
- To eval Dz associated with altered carbohydrate metabolism
- Diabetes mellitus (cat DKA)
- Bovine ketosis
- Pregnancy
- Accumulate in urine and milk before blood
- NOT DETECTED IN HEALTHY ANIMALS WITH GOOD NUTRITION
Carprofen physiologic effects that cause GI dz
- Decrease mucus secretion
- Increase acid secretion
- Famotidine raises pH of stomach
* antacids raise pH of stomach not a good combo with a RAW diet
Glucosamine or flucosamine…?
- Sugar that coats proteins
- increases with diabetes
- more reliable marker for diabetes than glucose for cats
Depomedrol
Pred injection
for cat asthma
Feeding a high fat diet dogs
- Can give a dog pancreatitis
* dark turkey meat at Thanksgiving - Can cause Ketones in urine
Diabetes mellitus in a nutshell
- Not making insulin or insulin resistant
=>
- Can’t break down carbohydrates for energy
=>
- Forced to use fatty acids for energey
=>
- Makes the ketones
Bovine Ketosis
- Dairy cows have insane energy requirements, break down any energy source available
- Ketones accumulate in urine and milk before blood
Urine Protein Results
1+ protein in normal animal - Jen doesn’t care
Interpret in context with spec grav and pH
-alkaline urine can cause false positive rxn since dipstick pad is acid-based
Common causes of proteinuria
- Urinary tract inflammation
- Hematuria
- Glomerular disease
Dipstick is VERY SUBJECTIVE
More accurate assessment of proteinuria
Urine protein to creatinine ratio (UP:UC)
We always care about protein in the urine b/c
- loss of albumin => oncotic pressure
- loss of antithrombin => hypercoagulability
Hemaglobinuria vs Hematuria
Hemoglobinuria => suspicious of intravascular hemolysis
- Remeber, Heme is a protein
Hematuria => would have to have a significant hemorrhage for protein in Urine
Positive Heme reactions
- Intact red blood cells
- Hemoglobin
- Myoglobin
RBCs lyse when spec grav
1.006
When urine is dilute RBCs lyse
Heme slide:
Positive reaction
Interpret results in light of….
- To attribute dipstick proteinuria entirely to hemorrhage, must have a 3+ heme rxn
- Will get a positive reaction with
- Intact RBCs (will sediment when centrifuge)
- Free hemoglobin from lysed RBCs
- Free myoglobin from damaged myocytes
- Need to interpret in light of
- Urine Collection Method (see more with cysto)
- USG (RBCs lyse when
- pH (RBCs lyse in alkaline pH)
- Plasma color
- Muscle enzymes (CK, AST)
- Ammonium sulfate precipitation can help to distinguish btwn myoglobin and hemoglobin