VTNE Clinical Laboratory Procedures 4 — Questions and Answers
Question 1: What is the normal packed cell volume (PCV) range for adult dogs?
- 20–30%
- 37–55% (Correct answer)
- 60–70%
- 10–20%
Correct answer: 37–55%
The normal PCV (hematocrit) for adult dogs is approximately 37–55%, with values below 37% indicating anemia.
Question 2: A cat's blood smear shows many erythrocytes with refractile inclusions near the cell membrane that stain blue with new methylene blue. This is MOST consistent with:
- Heinz bodies (Correct answer)
- Howell-Jolly bodies
- Basophilic stippling
- Siderotic granules
Correct answer: Heinz bodies
Heinz bodies are aggregates of denatured hemoglobin that stain with supravital stains like new methylene blue and are common in cats due to their susceptibility to oxidative damage.
Question 3: When collecting a urine sample by cystocentesis, which needle gauge and direction is most appropriate?
- 16-gauge needle, directed toward the bladder neck
- 22-gauge needle, directed into the bladder body (Correct answer)
- 18-gauge needle, into the urethra
- 25-gauge needle, into the renal pelvis
Correct answer: 22-gauge needle, directed into the bladder body
A 22-gauge needle directed into the body of the bladder is standard for cystocentesis to minimize trauma and obtain a sterile sample.
Question 4: Which chemistry value would you expect to be ELEVATED in a patient with cholestasis?
- BUN
- Creatinine
- Alkaline phosphatase (ALP) (Correct answer)
- Glucose
Correct answer: Alkaline phosphatase (ALP)
ALP is an enzyme that leaks from biliary epithelial cells during cholestasis, making it a key marker of bile duct obstruction or hepatobiliary disease.
Question 5: In a complete urinalysis, crystals identified as colorless coffin-lid shaped structures are most likely:
- Calcium oxalate monohydrate
- Struvite (magnesium ammonium phosphate) (Correct answer)
- Uric acid
- Cystine
Correct answer: Struvite (magnesium ammonium phosphate)
Struvite crystals classically appear as colorless three-to-six-sided 'coffin-lid' prisms and are common in alkaline urine.
Question 6: Which of the following is a zoonotic disease that can be detected on fecal examination?
- Toxoplasma gondii oocysts in cat feces (Correct answer)
- Anaplasma phagocytophilum morulae
- Dirofilaria immitis microfilariae
- Mycoplasma haemofelis
Correct answer: Toxoplasma gondii oocysts in cat feces
Toxoplasma gondii oocysts shed in cat feces are infectious to humans, especially immunocompromised individuals and pregnant women.
Question 7: A blood sample is hemolyzed when received at the laboratory. Which chemistry value is MOST likely to be falsely elevated due to hemolysis?
- Sodium
- Potassium (Correct answer)
- Albumin
- Total bilirubin
Correct answer: Potassium
Potassium is found in high concentrations inside red blood cells, so hemolysis releases intracellular potassium and artificially elevates serum potassium.
VTNE Clinical Laboratory Procedures 4
What is the normal packed cell volume (PCV) range for adult dogs?