Objectives: To retrospectively analyze diatom test cases of corpses in water and discuss the value of quantitative analysis of diatoms in the diagnosis of drowning.
Methods: A total of 490 cases of water-related death were collected. They were divided into drowning group and postmortem immersion group according to the cause of death. Diatoms in lung, liver, kidney tissue and water sample were analyzed quantitatively by microwave digestion-vacuum filtration-automated scanning electron microscopy (MD-VF-Auto SEM) method. The ratios of content of diatoms in lung tissue and water sample (CL/CD) were calculated.
Results: The results of diatom test for three organs (lung, liver and kidney) were all positive in 400 cases (85.5%); the content of diatom in lung, liver, kidney tissues, and water samples of drowning group were (113 235.9±317 868.1), (26.7±75.6), (23.3±52.2) and (12 113.3±21 760.0) cells/10 g, respectively; the species of diatom were (7.5±2.8), (2.6±1.9), (2.9±2.1) and (8.9±3.0) types, respectively; the CL/CD of drowning group and postmortem immersion group were (100.6±830.7) and (0.3±0.4), respectively.
Conclusions: Quantitative analysis of diatoms can provide supportive evidence for the diagnosis of drowning, and the parameter CL/CD can be introduced into the analysis to make a more accurate diagnosis of drowning.
目的: 对水中尸体硅藻检验案例进行回顾性分析，探讨硅藻定量分析在溺死诊断中的应用价值。方法: 收集水中尸体共490例，根据死因分为溺死组和死后入水组，采用微波消解-真空抽滤-自动扫描电子显微镜法对肺、肝、肾组织及水样进行硅藻定量分析，并计算肺组织与水样硅藻含量的比值（CL/CD值）。结果: 溺死组肺、肝和肾组织同时检出的有400例（85.5%），肺、肝、肾组织和水样中硅藻含量分别为（113 235.9±317 868.1）、（26.7±75.6）、（23.3±52.2）和（12 113.3±21 760.0）个/10 g，硅藻种类数分别为（7.5±2.8）、（2.6±1.9）、（2.9±2.1）、（8.9±3.0）种。溺死组和死后入水组CL/CD值分别为（100.6±830.7）、（0.3±0.4）。结论: 硅藻定量分析可为溺死诊断提供支持性证据，引入CL/CD值这一参数进行分析，能更准确地作出溺死的诊断。.
Keywords: diatom test; drowning; forensic pathology; microwave digestion-vacuum filtration-automated scanning electron microscopy method; quantitative analysis.