MLS Clinical Procedures & Protocols 4

Question 1

A patient's PT is 45 seconds and the laboratory mean normal PT is 12 seconds. What is the INR if the ISI of the thromboplastin used is 1.2?

Accepted Answer

3.75

Answer

INR = (PT patient / PT mean normal)^ISI = (45/12)^1.2 = (3.75)^1.2 ≈ 3.75; since ISI=1.2, the calculation yields approximately 3.75.

Question 2

Which condition is MOST likely if osmotic fragility testing shows increased RBC resistance to hemolysis in hypotonic saline?

Accepted Answer

Iron deficiency anemia

Answer

Iron deficiency produces hypochromic, microcytic RBCs with a larger surface-to-volume ratio, making them more resistant to osmotic lysis (decreased fragility).

Question 3

A lab's LIS interface drops and pending results cannot be auto-verified. What is the correct downtime procedure?

Accepted Answer

Manually phone all critical values and log on paper per downtime policy

Answer

Downtime procedures require manual reporting of critical values by phone and paper logging to ensure patient care is not interrupted.

Question 4

Which reagent strip test on a urine dipstick detects hydrogen peroxide produced by peroxidase-like activity of hemoglobin?

Accepted Answer

Blood/hemoglobin

Answer

The blood pad on a dipstick uses a peroxidase reaction: hemoglobin catalyzes oxidation of a chromogen by hydrogen peroxide, producing a color change.

Question 5

During a crossmatch, an unexpected antibody is detected in the patient's serum. What is the NEXT step?

Accepted Answer

Perform an antibody identification panel

Answer

An unexpected antibody requires an antibody identification panel to determine the specificity before selecting antigen-negative compatible blood.

(MLS) Medical Laboratory Scientist Practice Test

(MLS) Medical Laboratory Scientist Practice Test

MLS Clinical Procedures & Protocols 4