VTNE Laboratory Procedures 3 — Questions and Answers
Question 1: What does the term 'left shift' mean on a CBC differential?
- Decreased total white blood cell count
- Increased immature neutrophils (bands) in circulation (Correct answer)
- Shift of platelets to smaller size
- Increased eosinophil count
Correct answer: Increased immature neutrophils (bands) in circulation
A left shift refers to the presence of increased band neutrophils or earlier precursors in peripheral blood, indicating bone marrow release in response to increased demand.
Question 2: A fecal flotation using zinc sulfate solution is particularly useful for identifying:
- Tapeworm proglottids
- Giardia cysts (Correct answer)
- Coccidia oocysts only
- Nematode larvae
Correct answer: Giardia cysts
Zinc sulfate flotation (specific gravity ~1.18) is the preferred method for recovering Giardia cysts because it preserves cyst morphology better than sodium nitrate or sucrose solutions.
Question 3: Which electrolyte abnormality is most commonly associated with urethral obstruction in cats?
- Hypokalemia
- Hypernatremia
- Hyperkalemia (Correct answer)
- Hypochloremia
Correct answer: Hyperkalemia
Urethral obstruction causes post-renal azotemia and inability to excrete potassium, leading to life-threatening hyperkalemia that can cause cardiac arrhythmias.
Question 4: When reading a microhematocrit tube after centrifugation, what layer is found between the packed red cells and the plasma?
- Fibrin layer
- Buffy coat (Correct answer)
- Lipid layer
- Protein band
Correct answer: Buffy coat
The buffy coat is a thin whitish layer between the packed RBCs and plasma that contains white blood cells and platelets.
Question 5: Which coagulation test evaluates the extrinsic and common pathways?
- Activated clotting time (ACT)
- Activated partial thromboplastin time (aPTT)
- Prothrombin time (PT) (Correct answer)
- Buccal mucosal bleeding time (BMBT)
Correct answer: Prothrombin time (PT)
Prothrombin time (PT) evaluates the extrinsic (factor VII) and common (factors X, V, II, fibrinogen) pathways of coagulation.
Question 6: A serum chemistry panel shows markedly elevated ALT and AST with only mildly elevated ALP in a dog. This pattern most suggests:
- Primary bone disease
- Hepatocellular damage (Correct answer)
- Cholestasis
- Pancreatic disease
Correct answer: Hepatocellular damage
ALT and AST are hepatocellular enzymes; marked elevation of both with minimal ALP elevation is most consistent with hepatocellular injury rather than cholestasis.
Question 7: Which parasite is diagnosed by the Baermann technique?
- Toxocara canis
- Angiostrongylus vasorum larvae (Correct answer)
- Dipylidium caninum
- Ancylostoma duodenale eggs
Correct answer: Angiostrongylus vasorum larvae
The Baermann technique uses gravity and larval migration toward warmth/moisture to recover lung and tissue nematode larvae (e.g., Angiostrongylus, Aelurostrongylus) from feces.
VTNE Laboratory Procedures 3
What does the term 'left shift' mean on a CBC differential?