Evaluation and comparative analysis of minimal formalin containing compound fixatives

Abstract

Introduction: Fixation is the crucial step in the practice of diagnostic pathology. Formalin has been used as a general fixative for more than a century. The IARC (International Agency for Research on Cancer) reported that there is a causal association between formalin exposure and leukemia and nasopharyngeal carcinoma. Hence this study was done to find an alternative fixative to minimize formalin exposure in histopathology laboratory. Materials and Methods: 100 specimens were fixed in 3 different minimal formalin containing compound fixatives composed of ethanol, glycerin, formalin (EFG fixatives)and hypotonic saline at fixation time of 10, 8 and 7 hours. The processed specimens were analyzed for fixation artifacts, staining characteristics and cytoarchitectural features and compared with conventional formalin fixation. Results: Cytoarchitectural features were well preserved as conventional formalin fixation in both EFG I and EFG II at 8 and 10 hours of fixation, and with inadequate fixation characters at 7 hours. EFG II was found to evaporate less formaldehyde vapor than 10% buffered formalin and fixation time reduced upto 8 hours. EFG III resulted in poor preservation of tissues in all three fixation times. Conclusion: As formaldehyde is a group 1 human carcinogen, it should be replaced by less toxic fixatives in histopathology laboratories. The present study highlights that minimal formalin containing EFG fixatives can be easily prepared in the laboratory and their effectiveness in routine histopathology examination is comparable with conventional formalin fixation. Keywords: Compound fixatives, Architecture, Fixation, Formalin toxicity, Histopathology.