EVALUATION OF THE EFFICACY OF VARIOUS XYLENE SUBSTITUTES AS A CLEARING AGENT IN TISSUE PROCESSING: A COMPARATIVE STUDY

Abstract

Conventional tissue processing is still remains the gold standard. Tissue processing is a physical process that involves chemical solutions reacting with biological specimens. The main purpose of tissue processing is to embed the tissue in solid medium, firm enough to support the tissue and give it sufficient rigidity to enable thin sections to be cut and soft enough not to damage the knife or tissue. For any tissue specimen to undergo diagnosis, it has to follow procedural steps such as fixation, dehydration, clearing, impregnation, embedding, sectioning and staining. Clearing is the process of replacing the dehydrating solution (which is not miscible with the embedding medium) with a substance which will be miscible with alcohol and the embedding medium. The most commonly used clearing agent is xylene. It has excellent clearing capabilities. But it cause unwelcome effects on the various system of the human body like on skin, eyes, nervous system, blood, liver and kidneys as reported by Kandyala et al. In the present study, we evaluate the efficacy of three materials like Kerosene, Turpentine and Olive oil other than xylene which are substitutes as a clearing agent in tissue processing and observe their effect on staining characteristics and compare with xylene. It is better promoting to eliminate xylene from the histology laboratory is a duty of those who are in decision-making positions. Since our study was limited in sample size and there are very less studies comparing all the four chemicals in clearing agent, it is recommended to carry this study in large scale with addition of different substitutes and analyzing with multiple observers.