STP Clinical Sciences 3

Question 1

A patient with chronic kidney disease has a GFR of 18 mL/min/1.73m². Which CKD stage does this represent?

Accepted Answer

Stage 4

Answer

CKD Stage 4 is defined by a GFR of 15-29 mL/min/1.73m², indicating severely decreased kidney function and approaching the threshold for renal replacement therapy.

Question 2

Which immunoglobulin class is the predominant antibody in seronegative rheumatoid arthritis that targets citrullinated peptides?

Accepted Answer

IgG

Answer

Anti-citrullinated protein antibodies (ACPAs), including anti-CCP antibodies, are predominantly of the IgG class and are highly specific for rheumatoid arthritis.

Question 3

A 30-year-old male has hemoglobin electrophoresis showing: HbS 80%, HbF 18%, HbA2 2%, HbA absent. Which condition does this indicate?

Accepted Answer

Sickle-beta thalassemia (S/β0)

Answer

HbS 80% with absent HbA and elevated HbF, with normal HbA2 is characteristic of sickle-beta-zero thalassemia, where no HbA is produced due to the absent beta-globin chain.

Question 4

In the interpretation of a Western blot for HIV confirmation, which bands must be present for a result to be considered positive per CDC criteria?

Accepted Answer

At least one band from gp120, gp41, or p24

Answer

CDC criteria require at least two of the following bands for a positive HIV Western blot: gp160/120, gp41, and p24, but any single band from these key antigens requires additional testing.

Question 5

A coagulation screen shows: PT normal, APTT prolonged, 1:1 mix corrects the APTT. Which factor deficiency is most likely?

Accepted Answer

Factor VIII deficiency

Answer

Isolated prolonged APTT that corrects on 1:1 mixing indicates a factor deficiency (not inhibitor) in the intrinsic pathway; Factor VIII deficiency (hemophilia A) is the most common cause.

(STP) Scientist Training Programme Practice Test

(STP) Scientist Training Programme Practice Test

STP Clinical Sciences 3