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Tissue handling

Tissue fixation

The fixation time in formalin should be at least 24 hours for small specimens and at least 48 hours for larger specimens. 

If the fixation time is too short, the tissue will partly be alcohol fixed, causing a heterogeneous immunoreactivity, particularly in case of proteolytic pre-treatment

If the fixation time is too long, some epitopes may be increasingly difficult to detect, unless the demasking is completely optimized. Delayed fixation may result in loss of antigeneity as well as non-specific immunoreaction.

 

Decalcification

Decalcification of calcified tissue in strong acids causes loss of many epitopes, while weak acids and EDTA are harmless, provided that the tissue has been properly formalin fixed in advance.

   
   
   
   
MV/SN/AS

Last update 21-09-2005