HT Immunohistochemistry Procedures 3

Question 1

What is the main advantage of polymer-based IHC detection systems over avidin-biotin systems?

Accepted Answer

Elimination of endogenous biotin interference

Answer

Polymer-based systems avoid biotin entirely, eliminating false positives caused by endogenous biotin found in liver, kidney, and other tissues.

Question 2

Which tissue type is most likely to cause false-positive results due to high endogenous biotin content?

Accepted Answer

Liver and kidney

Answer

Liver and kidney contain high levels of endogenous biotin, which can bind streptavidin and cause background staining in avidin-biotin-based IHC systems.

Question 3

Which pH is most commonly used with citrate buffer for heat-induced antigen retrieval?

Accepted Answer

pH 6.0

Answer

Citrate buffer at pH 6.0 is the most widely used HIER solution for unmasking antigens fixed with formalin in routine histopathology.

Question 4

Which IHC marker is commonly used to identify T-lymphocytes in tissue sections?

Accepted Answer

CD3

Answer

CD3 is a pan-T-cell marker expressed on the surface of T-lymphocytes and is routinely used in IHC to identify T-cells in tissue.

Question 5

In IHC, the purpose of a blocking step with normal serum is to:

Accepted Answer

Reduce nonspecific background by blocking free tissue protein binding sites

Answer

Normal serum from the same species as the secondary antibody saturates nonspecific binding sites in the tissue, reducing background staining.

(HT) Histotechnician Certification Practice Test

(HT) Histotechnician Certification Practice Test

HT Immunohistochemistry Procedures 3