Clinical Chemistry and Urinalysis Instruction
Clinical Chemistry and Urinalysis Instruction tests teaching of panel selection, quality control, analyte interpretation, and urine sediment examination. The exam emphasizes preanalytical effects, reference intervals, and correlation of chemistry with urinalysis rather than memorized disease lists.
Core rules
- Protect samples from hemolysis, lipemia, icterus, and delay; separate plasma or serum promptly when the analyte requires it.
- Interpret against species and age-appropriate reference intervals and consider analytical error before disease.
- For urinalysis, use a refractometer for specific gravity; dipstick results are screening only and require sediment and chemistry correlation.
- Examine sediment promptly at 10x and 40x; report cells, casts, crystals, and bacteria with quantity and context.
- Connect azotemia to urine concentrating ability, and liver enzymes to bile acids or function tests when appropriate.
Worked example
A cat has increased creatinine and BUN with urine specific gravity of 1.012. The reasoning: dilute urine in the face of azotemia suggests loss of concentrating ability and supports renal azotemia; a specific gravity of 1.045 would suggest prerenal causes. The teaching point is to interpret the pair, not the chemistry alone.
Traps
Using dipstick specific gravity, reading sediment after refrigeration, ignoring lipemia, and treating a single abnormal analyte as a diagnosis. Also avoid missing that some crystals are normal in certain species.