Technical note: Nitric acid addition reduces residues and increases diatom-detection efficiency in the diatom testing of closed organs

This study assessed the ability of the nitric acid addition (NAAdd) method to reduce residues and maintain diatom detection efficiency for diagnosing drowning. Two experiments (1 and 2) were conducted wherein liver samples and diatom-added liver samples were digested using fuming nitric acid with or without the NAAdd method, respectively, for slide preparation. Residues and diatom counts were compared between the NAAdd and conventional methods. The NAAdd method reduced residues in experiment 1 and showed markedly higher diatom counts in most cases across both experiments. This study suggests that the NAAdd method effectively reduces residues while maintaining diatom detection efficiency.