Medical Technologist Test Medical Technologist Knowledge 5

Question 1

Which test is used to differentiate Streptococcus pyogenes (Group A) from other beta-hemolytic streptococci?

Accepted Answer

Bacitracin susceptibility

Answer

Group A streptococci (S. pyogenes) are susceptible to bacitracin, differentiating them from other beta-hemolytic streptococcal groups.

Question 2

A patient's red blood cells fail to agglutinate with anti-A, anti-B, and anti-D, but the serum has no alloantibodies. This pattern is consistent with:

Accepted Answer

Bombay phenotype (Oh)

Answer

Bombay phenotype lacks H antigen, so cells type as O but also lack normal H antigen, and serum contains anti-H that reacts with all common donor cells.

Question 3

The principle behind the ELISA (enzyme-linked immunosorbent assay) technique is:

Accepted Answer

Enzyme-labeled antibody binding detected by color change upon substrate addition

Answer

ELISA uses an enzyme-conjugated antibody; addition of substrate causes a colorimetric reaction proportional to the amount of antigen or antibody present.

Question 4

Which finding on a peripheral smear is characteristic of iron deficiency anemia?

Accepted Answer

Microcytosis with hypochromia and target cells

Answer

Iron deficiency anemia produces microcytic, hypochromic red cells, often with target cells due to excess membrane relative to hemoglobin content.

Question 5

The confirmatory test for HIV infection after a reactive screening immunoassay is:

Accepted Answer

HIV-1/HIV-2 antibody differentiation immunoassay or HIV RNA NAT

Answer

Per the current CDC 2014 algorithm, a reactive 4th-generation immunoassay is confirmed with an HIV-1/HIV-2 antibody differentiation assay, followed by HIV-1 RNA NAT if results are discordant.

Medical Technologist Test Practice Test

Medical Technologist Test Practice Test

Medical Technologist Test Medical Technologist Knowledge 5