Abstract
About 54 medical accidents in the handling of the fixing solution for histopathology have occurred in the last eight years in Japan. In these accidents, formalin is misused with medicines and other compounds such as mint oil, saline, and alcohol. Incidents in which a patient’s specimen is placed in a fixing solution into which another patient’s specimen was previously put still occur. The absence of a system with which opened and unopened solutions can be differentiated is also another factor. In this study, a method of sealing a bottle with a lid and the coloration of formalin were developed to prevent accidents, and their usefulness was verified for four years. A practical coloration of formalin uses less than 0.01% dyes than a bromothymol-blue or a phenol-red solution used singly or in a mixture. This coloration method is a detection tool for formalin based on color tone, and a pH indicator showed that the method neither changes the color nor causes discoloration of specimens. The method showed long stability of specimens, and tissue and cell damage was minimal. Furthermore, a sealing tape is applied to the lid of a fixing bottle, and the “post-ablation” label is embossed on the tape to differentiate used from unused formalin, which makes checking easy. Products equipped with a “coloration” and a “seal” were used in about 140,000 specimens, the incidence rate was 0%, and good results were obtained as compared with cases without using such products. Accordingly, the proposed sealing method and formalin coloration are novel tools and help prevent medical accidents originating from incorrect formalin fixing.
