HT Immunohistochemistry Procedures 2

Question 1

Which antigen retrieval method uses a pressure cooker or autoclave to expose epitopes?

Accepted Answer

Heat-induced epitope retrieval (HIER)

Answer

Heat-induced epitope retrieval (HIER) uses high-temperature methods such as pressure cookers, autoclaves, or water baths to unmask formalin-fixed epitopes.

Question 2

What is the purpose of a positive control slide in IHC?

Accepted Answer

To verify that the entire IHC procedure is working correctly

Answer

A positive control slide contains tissue known to express the target antigen, confirming that the staining procedure, reagents, and antibodies are all functioning correctly.

Question 3

In a streptavidin-biotin IHC system, which molecule binds directly to the primary antibody?

Accepted Answer

Biotinylated secondary antibody

Answer

The biotinylated secondary antibody binds to the primary antibody, after which streptavidin-enzyme complex binds the biotin tag.

Question 4

Which chromogen produces a brown end product when used with horseradish peroxidase in IHC?

Accepted Answer

DAB (3,3'-diaminobenzidine)

Answer

DAB (3,3'-diaminobenzidine) reacts with horseradish peroxidase to produce a permanent brown precipitate at the antigen site.

Question 5

Endogenous peroxidase activity in tissue is typically blocked using:

Accepted Answer

Hydrogen peroxide in methanol or water

Answer

Hydrogen peroxide solution quenches endogenous peroxidase activity, preventing false-positive background when using HRP-based detection systems.

(HT) Histotechnician Certification Practice Test

(HT) Histotechnician Certification Practice Test

HT Immunohistochemistry Procedures 2