Evaluation of Ethanol-based Fixatives as a Substitute for Formalin in Diagnostic Clinical Laboratories

Abstract

The use of formalin as a fixative in the histology laboratory is a potential danger to laboratory workers. Formalin results in common complaints such as eye, nose, and throat irritations, and less commonly neurological disorders such as bronchitis and neoplasia. A substitute of formalin is needed in a society that is becoming increasingly ‘work safe’ conscious. Ethanol-based fixatives were compared with formalin for their ability to preserve tissue and cellular morphology, to retain antigenicity, and to facilitate the diagnosis of complex pathological specimens. Ethanol-based fixative F13 (60% ethanol, 20% methanol, and 7% polyethylene glycol) was statistically significantly different from formalin, providing superior preservation of tissue morphology. In 20 surgical cases, F13, and formalin were equally able to fix tissue to allow accurate diagnoses.

Immunohistochemical staining was generally enhanced using F13 fixed tissue without the use of antigen retrieval as compared to formalin fixed tissue. However, in cases where staining was unacceptable using F13 fixed tissue, the introduction of heat antigen retrieval had a marked effect of increasing antigen staining. The introduction of F13 as a fixative for histology laboratories should reduce the hazards associated with formalin without compromising clinical tests. (The J Histotechnol 23:299, 2000)

Keywords:

• antigen retreival
• F13
• immunohistochemistry
• methanol
• polyethylene glycol