Histomorphological Assessment of Formalin versus Nonformalin Fixatives in Diagnostic Surgical Pathology
Jayaprakash Kubalady Shetty1, Hannah Fathima Babu1, Kishan Prasad Hosapatna Laxminarayana1
1Department of Pathology, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru, Karnataka, India.
Insights
Formalin fixation is effective but poses health risks. Methyl alcohol and acetone offer comparable tissue preservation, suggesting they are viable alternatives in pathology and research.
Area of Science:
- Histopathology
- Toxicology
- Biomedical Research
Background:
- Formalin (10%) is a widely used, economical tissue fixative in diagnostic pathology.
- Formalin poses significant health risks, including carcinogenicity and corrosive effects.
- The 'formalin dogma' has historically limited the exploration of alternative fixatives.
Purpose of the Study:
- To compare the efficacy of formalin, methyl alcohol, and acetone as tissue fixatives.
- To evaluate alternative fixatives for diagnostic pathology and medical research applications.
Main Methods:
- Ninety autopsy tissue samples (liver, skeletal muscle) were fixed using 10% formalin, 70% methyl alcohol, and 100% acetone.
- Fixation time, tissue architecture, cell and nuclear morphology, and staining uniformity were assessed.
Main Results:
- Formalin provided rapid fixation; however, alcohol and acetone demonstrated satisfactory tissue architecture and cell borders.
- Formalin yielded superior cytoplasm and nuclear contour preservation.
- Chromatin texture and staining uniformity were comparable across all three fixatives.
Conclusions:
- While formalin excels in certain parameters, methyl alcohol and acetone offer comparable results.
- Given formalin's health hazards, alcohol and acetone are suitable alternatives for tissue fixation.
- Complete substitution of formalin is feasible in diagnostic pathology and research without compromising quality.
Abstract:
Introduction Fixation is the critical step in the preservation of tissues in diagnostic pathology. The formalin is an economical and excellent fixative with the inherent property of adequate fixation. The well-established side effects of formalin include mucosal irritation, upper respiratory diseases, and corrosive injury to the gastrointestinal tract. In addition, substantial evidence exists regarding the potential role of formaldehyde as a human carcinogen. The carcinogenic and toxic effects of formalin encourage searching for alternative fixatives for tissue fixation. However, "the formalin dogma" has severely hampered the search for alternative fixatives for many years. Material and Methods Ninety tissues of liver and skeletal muscle obtained during autopsies were immersed in adequate amounts of the following fixatives: formalin (10%), methyl alcohol (70%), and acetone (100%). The comparison among the three was made based on time for fixation, preservation of tissue architecture, cell borders, cytoplasm, nuclear contours, chromatin texture, and uniformity of staining. Results The tissue preserved in formalin undergoes rapid fixation compared with alcohol and acetone. The tissue architecture, cell border characteristics of alcohol and acetone was found satisfactory compared with formalin. The cytoplasm and nuclear contour were superior with the formalin. The chromatin texture and uniformity of staining were similar with all the three fixatives. Conclusion The formalin is considered superior to most of the parameters, whereas both methyl alcohol and acetone showed nearly equivalent scores. Hence, owing to the potential human health hazards and carcinogenicity of formalin, no rational reasons hamper the complete substitution of formalin with alternative fixatives such as alcohol and acetone in diagnostic pathology and medical research.
