Effects of preanalytical variables on the detection of proteins by immunohistochemistry in formalin-fixed, paraffin-embedded tissue.

TLDR

Formalin fixation and paraffin embedding are the gold standard for tissue preservation in immunohistochemistry, yet the influence of fixation and processing variables on assay effectiveness has received limited attention. This study aimed to pinpoint specific fixation and processing steps that affect immunostaining, quantify reported effects, and identify variables needing further investigation. We surveyed 39 primary research articles on preanalytical variables, extracted their reported thresholds, and compared them with established guidelines for formalin‑fixed, paraffin‑embedded specimens. Of 62 identified preanalytical variables, 27 had been examined in the literature, and a meta‑analysis highlighted 15 variables with notable impacts on immunohistochemical results.

Abstract

Abstract Context.—While formalin fixation and paraffin embedding has become a universal mechanism of tissue preservation and a gold standard for immunohistochemistry, fixation and processing variables that may confound assay effectiveness have received little attention from the scientific community. Objective.—To identify discrete steps in specimen fixation and processing that may impact immunostaining, assess the magnitude of reported effects in the literature, and highlight preanalytical variables that require further investigation. Data Sources.—Thirty-nine primary research articles that investigated immunohistochemical effects of 1 or more preanalytical variables were identified by our literature survey. Thresholds identified in the literature were then compared with published immunohistochemistry guidelines for formalin-fixed, paraffin-embedded specimens. Conclusions.—Of the 62 preanalytical variables identified, 27 were examined in published research. Meta-analysis revealed 15 preanalytical variable...