Evaluation of a New Compound Fixative: A step towards limited formalin exposure

Introduction: The aim of the study was to minimize formalin exposure in histopathology laboratory and analyze the fixation characteristics of a group of formalin containing compound fixatives with reduced concentration of formaldehyde. Materials and Method: A minimal formalin containing fixative was prepared with varying concentrations of formalin, ethanol, glycerin and hypotonic saline. The pH of the fixative was maintained below 7.2 to 7.4. Multiple human tissue materials of varying sites, organs, and lesions were utilized. Tissue slices were immediately fixed in the prepared compound fixative. A comparative analysis of fixation and staining qualities were done. Result: There is no significant difference between 10% NBF and new fixative at 8 and 10 hours fixation and the new fixative is comparable to 10% NBF in preserving cytoarchitectural features at 8 and 10 hours of fixation. A total of 32 out of 35 cases had a maximum score 9 at 8 and 10 hours fixation. The formaldehyde vapor from the compound fixatives were qualitatively measured and found to be 3 times less in the laboratory atmosphere. Conclusion: The present study demonstrates that a minimal formalin containing fixative can be easily prepared in the laboratory and they are suitable for histopathological examination of routine surgical specimens. The effectiveness of this new compound fixative is comparable to conventional formalin fixation with an improved air quality of the working laboratory and considerably reduced formalin vapor density. Keywords: Compound fixative, Cytoplasmic features, Formalin toxicity, Formalin vapor, Histopathology, Nuclear features