Overfixation effects?

Study for the CAMLPR Histology Practice Test. Study with flashcards and multiple choice questions, each question has hints and explanations. Get ready for your exam!

Overfixation happens when tissue is fixed for too long with fixatives like formaldehyde, causing excessive cross-linking of proteins. This extra cross-linking makes the tissue become hard and often shrink as water and structural components are altered. It also masks antigenic sites, so epitopes are less accessible to antibodies or stains, leading to weaker or absent staining in immunohistochemistry and related techniques. Increased staining is not expected because the cross-links hinder, rather than enhance, antigen exposure. Autolysis is a separate degeneration process driven by endogenous enzymes after death, not a result of fixation time. So the combination of tissue hardness, shrinking, and masking of antigenicity best describes overfixation.