Better choice of fixatives provides better histological details of the alveolar-capillary interface

Aims: To evaluate lung disease, pulmonary tissues should be fixed by inflation. However, many histological sections prepared after inflation fixation show wire‐like alveolar septa with capillary collapse. We investigated the reason for this artefact.Methods: To evaluate the effect of fixatives, we used the following commercially available solutions: regular 10% neutral buffered formalin (NBF), 20% NBF, 10% and 5% formalin prepared by diluting the 20% NBF, modified formalin solution as a substitute for 10% NBF, and 10% formalin prepared by diluting the 100% formalin without any buffers.Results: The osmolarity of the fixative was found to be responsible for the collapse artefact. Ten per cent formalin, prepared by diluting 100% formalin, the commercially available substitute for 10% NBF, and 5% formalin prepared by diluting 20% NBF, yielded the best pulmonary tissue morphology, including that of the alveolar‐capillary interface.Conclusions: Pulmonary physicians and pulmonary pathologists should use a suitab...