Laboratory Techniques and Diagnostic Procedures Flashcards

When preparing a bacterial culture swab from a wound, which transport medium is most appropriate to maintain organism viability during shipping?

Answer: Amies or Stuart transport medium

Amies and Stuart transport media maintain moisture and preserve bacterial viability without allowing significant growth or drying during transit to the lab.

A BUN (blood urea nitrogen) to creatinine ratio greater than 20:1 in a dehydrated dog most likely indicates what type of azotemia?

Answer: Pre-renal azotemia due to reduced renal perfusion

Pre-renal azotemia causes disproportionate BUN elevation relative to creatinine because the kidney reabsorbs urea more avidly when perfusion is low, raising the BUN:Cr ratio above 20:1.

Which type of microscope objective is used to identify microfilariae in a modified Knott's test preparation?

Answer: Low power (10×)

The 10× objective (low power) is used first to scan for microfilariae because they are large enough to be visible at low magnification and are easier to find across the field.

What does the term 'isosthenuria' mean in the context of a urinalysis?

Answer: Urine specific gravity equal to that of glomerular filtrate (1.008–1.012), indicating tubular inability to concentrate or dilute

Isosthenuria (USG 1.008–1.012) means the kidney can neither concentrate nor dilute urine beyond plasma ultrafiltrate, signaling severe tubular dysfunction.

A Diff-Quik stained impression smear from a skin lesion reveals numerous round organisms with a clear halo inside macrophages. What is the most likely organism?

Answer: Cryptococcus neoformans

Cryptococcus neoformans appears as round yeast with a prominent clear polysaccharide capsule (halo) and is commonly found inside macrophages on cytology.

Which laboratory finding is most consistent with a regenerative anemia in a dog?

Answer: Increased polychromasia and elevated reticulocyte count

Regenerative anemia is characterized by increased reticulocytes (immature RBCs) and polychromasia (blue-tinged cells on Wright stain) as the bone marrow responds to RBC loss.

When collecting a urine sample by cystocentesis, what is the primary advantage over a free-catch sample for culture and sensitivity testing?

Answer: The sample is collected without contamination from the urethra, prepuce, or vulva

Cystocentesis bypasses the lower urogenital tract, eliminating environmental and commensal bacterial contamination and providing a sterile bladder sample ideal for culture.