Laboratory Procedures Flashcards

What does the term 'left shift' mean on a CBC differential?

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.

A fecal flotation using zinc sulfate solution is particularly useful for identifying:

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.

Which electrolyte abnormality is most commonly associated with urethral obstruction in cats?

Answer: Hyperkalemia

Urethral obstruction causes post-renal azotemia and inability to excrete potassium, leading to life-threatening hyperkalemia that can cause cardiac arrhythmias.

When reading a microhematocrit tube after centrifugation, what layer is found between the packed red cells and the plasma?

Answer: Buffy coat

The buffy coat is a thin whitish layer between the packed RBCs and plasma that contains white blood cells and platelets.

Which coagulation test evaluates the extrinsic and common pathways?

Answer: Prothrombin time (PT)

Prothrombin time (PT) evaluates the extrinsic (factor VII) and common (factors X, V, II, fibrinogen) pathways of coagulation.

A serum chemistry panel shows markedly elevated ALT and AST with only mildly elevated ALP in a dog. This pattern most suggests:

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.

Which parasite is diagnosed by the Baermann technique?

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.