MLS Clinical Testing & Analysis 2

Question 1

A patient's serum glucose is 54 mg/dL on a fasting specimen. Which confirmatory step is most appropriate?

Accepted Answer

Repeat testing on a new fasting specimen

Answer

A fasting glucose of 54 mg/dL is hypoglycemic and should be confirmed with repeat testing on a fresh specimen to rule out pre-analytical errors.

Question 2

Which reagent in the Wright-Giemsa stain is responsible for staining acidic cellular components pink/red?

Accepted Answer

Eosin Y

Answer

Eosin Y is the acidic dye in Wright-Giemsa that binds to basic (positively charged) cellular components such as hemoglobin and eosinophil granules, staining them pink to red.

Question 3

A PT result is markedly prolonged but the PTT is normal. Which factor deficiency is most consistent with this pattern?

Accepted Answer

Factor VII

Answer

Factor VII is the only clotting factor unique to the extrinsic pathway; its deficiency prolongs PT while leaving PTT normal.

Question 4

A urine specific gravity of 1.001 most likely indicates:

Accepted Answer

Diabetes insipidus or overhydration

Answer

Specific gravity of 1.001 represents maximally dilute urine, consistent with diabetes insipidus or excessive fluid intake.

Question 5

In the Kirby-Bauer disk diffusion method, which standard is used to prepare the bacterial inoculum?

Accepted Answer

0.5 McFarland standard

Answer

CLSI guidelines specify a 0.5 McFarland turbidity standard (~1–2 × 10⁸ CFU/mL) for inoculum preparation in Kirby-Bauer testing.

(MLS) Medical Laboratory Scientist Practice Test

(MLS) Medical Laboratory Scientist Practice Test

MLS Clinical Testing & Analysis 2