Module 12: Immunohistochemical Staining Flashcards
3 IHC labelling methods:
Enzyme/chromogen, colloidal gold, fluorochromes
What is the most common type of label used in IHC?
Enzyme/chromogen
Why is tissue preservation and processing so important in IHC?
Poor preservation and processing may result in antigen destruction
What is the most common fixative used prior to IHC staining?
Formalin based
What is the pretreatment of tissue to unmask antigens termed?
Antigen retrieval
What is the process used to prevent endogenous enzymes, such as peroxidase, from taking part in the enzyme/chromogen reaction in IHC techniques called?
Blocking
List 2 common enzymes used in IHC staining
Horseradish peroxidase, calf intestine alkaline phosphatase
The commonly used chromogen DAB gives what what colour end product?
Brown
The commonly used chromogen AEC gives what what colour end product?
Rose-red
Is the direct method more or less sensitive than the indirect method?
Less sensitive
Avidin used the ABC (avidin-biotin conjugate) method is obtained from what source?
Egg white
What is the benefit of using Streptavidin in the LSAB (labeled streptavidin-biotin) method compared to avidin in the ABC method?
Streptavidin results in less nonspecific staining
True or false: Biotin blocking is not required in polymer detection
True
True or false: Resinous mounting media should be used if the chromogen is AEC
False
True or false: Harris hematoxylin is the counterstain of choice for all methods using alkaline phosphates as a chromogen
False
True or false: Serum blocking may be performed to prevent nonspecific binding of the primary antibody
True
True or false: A positive control only needs to be run when a new batch of primary antibody is received
False
True or false: The sensitivity of polymeric detection is similar to LSAB
True
