Immunohistochemical (IHC) stains can be helpful in diagnostic pathology. They can sometimes but not always be used successfully on necrotic or decomposed tissue.
Problems that may be encountered:
(1) loss and/or degradation of target antigen
(2) increase in nonspecific/background staining
(3) loss of cellular details
Approaches to reduce problems:
(1) careful use of positive and negative controls
(2) pretreatment of sections to reduce nonspecific staining
(3) use of a method to reduce bias (double blind reading, digital analysis)
(4) optimizing tissue fixation
(5) taking steps to reduce tissue loss during the many staining steps
(6) examining multiple blocks from the target area, looking for better preserved foci