Analysis of false-positive results of diatom test in the diagnosis of drowning—would not be an impediment

Shen, Xuefeng; Liu, Yang; Cheng, Xiangdong; Chen, Zheng; Huang, Jing‐Fei; Shi, He; Xu, Quyi; Cheng, Jianding; Liu, Chao; Zhao, Jian

doi:10.1007/s00414-019-02021-4

Cited by 25 publications

(7 citation statements)

References 12 publications

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“…Moreover, the inhalation of diatoms should be considered an additional mechanism of diatom penetration in living animals (33, 34). The possibility of false positive diatom results has been previously reported in human forensic pathology (35). However, the human literature on antemortem diatom penetration is highly controversial.…”

Section: Discussionmentioning

confidence: 90%

Diagnosis of Drowning and the Value of the Diatom Test in Veterinary Forensic Pathology

et al. 2019

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The detection of diatoms into the organs is considered an important “biological marker” for the diagnosis of drowning in human pathology, but it still has a high possibility for false positive results. The aims of this study were: (1) to evaluate the contribution of pathological examination in drowning cases and (2) to investigate the differences in the number and location of diatoms between animals who died in drowning and non-drowning conditions. For these purposes, 30 dead adult dogs were selected for the study and subdivided into five groups. The group A comprised six cadavers dead for drowning; the group B comprised six control animals; the groups C, D, and E comprised six animals dead for causes other than drowning and subsequently immersed in water for 24, 48, and 72 h, respectively. On each animal, a complete macroscopic and histological examination and diatom test were performed. Diatoms test and quantification were also performed on drowning mediums. Pathological findings of the animals in the group A showed pulmonary congestion, oedema, and hemorrages in the lung. However, similar injuries were also observed in control and experimentally submerged cadavers. In contrast, we observed a statistically differences between drowning animals and all experimentally submerged groups and control animals regarding diatom numbers recovered from organ tissue samples (p < 0.05). Therefore, these findings suggest that the number of diatoms may be used as a valid tool to differentiate animals who died in drowning and non-drowning conditions, even if the latter were found in an aquatic environment.

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Section: Discussionmentioning

confidence: 90%

Diagnosis of Drowning and the Value of the Diatom Test in Veterinary Forensic Pathology

et al. 2019

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“…However, the MD-VF-Auto SEM method is extremely sensitive to diatom detection; therefore, there may be false-positive results due to contamination during sample collection. To solve this problem, Shen et al [ 13 ] quantitatively compared diatoms from false-positive cases and real drowning cases using the MD-VF-Auto SEM method and found that the number of diatoms in non-drowning corpses and death by drowning corpses was significantly different.…”

Section: Microwave Digestion-vacuum Filtration-automatic Scanning Elementioning

confidence: 99%

Research advances in forensic diatom testing

Zhou

Cao

Huang

et al. 2020

Forensic Sciences Research

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In forensic practice, it is difficult to determine whether a dead body in the water resulted from drowning or from disposal after death. Diatom testing is currently an important supporting technique for the determination of death by drowning and of drowning sites, even though it is a time-consuming and laborious task. This article reviews the development of diatom testing over the decades and discusses a new method for the potential application of deep learning in diatom testing.

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“…Using the multiplex PCR system, no peaks were observed at any lungs, liver, or kidney samples of the ten nondrowning cases (Table 4). However, the corresponding results of MD‐VF‐Auto SEM method, as well as our previous studies had demonstrated that a few diatoms could be observed in the liver and kidney tissues of nondrowned bodies [23]. Because diatoms are almost ubiquitous, being inhabitants of soil, water supplies and air, there are many possible ways causing diatoms deposition in the bodies, which may interfere with the diagnosis of drowning [24].…”

Section: Resultsmentioning

confidence: 99%

“…According to the basic principles of diatom tests, to draw a confirmative conclusion of death by drowning, diatoms over 20 valves/10 g tissue should be found in lung tissue, and diatoms over 5 valves/10 g tissue should be discovered in at least one distant organ such as the liver and kidney [26]. However, analysis of false‐positive results of diatom tests indicated that the number of diatoms in the liver or kidney tissues of nondrowning bodies may be more than 5 valves/10 g tissue [23], and diatoms over 5 valves/10 g tissue could even be observed in the bone marrow [27]. Therefore, it may be risky to draw a conclusion only based on the morphological observation of diatoms when a few diatoms were found in distant organs.…”

Section: Resultsmentioning

confidence: 99%

“…Thirty drowning cases and ten nondrowning cases were carefully selected under the inclusion criteria described in our previous study [23]. According to the Chinese standardized diatom test method of Detection the Diatoms in Human Tissues and Organs by Digesting Organic Matter with Nitric Acid, GA/T813—2008 , tissue samples were cut from the lower lobe of the right lung, the right lobe of the liver, and the left kidney of each body using disposable scalpels and gloves.…”

Section: Methodsmentioning

confidence: 99%

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Development and application of a multiplex PCR system for drowning diagnosis

Cheng

Xu²,

et al. 2021

Electrophoresis

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In recent years, the DNA detection of drowning‐related diatoms, cyanobacteria, and aeromonas has gradually attracted interest from forensic scientists. In this study, we described the validation and application of a novel multiplex PCR system. This system integrated 12 fluorescently labelled primers designed to amplify specific genes of diatoms, cyanobacteria, and aeromonas. The specificity studies demonstrated that this multiplex PCR system could detect nine species of diatom, seven species of cyanobacteria, and five species of aeromonas, all of which were drowning‐related and widely distributed in various water circumstance of southern China. The sensitivity studies indicated that the limit concentration of template DNA was 0.0125 ng. Besides, this multiplex PCR system had good performance in sizing precision and stability, but it is not suitable for degraded DNA samples. The application into forensic casework showed that all the tissue samples from ten nondrowning cases showed negative results, and the positive rates of lung, liver, kidney, and water samples from 30 drowning bodies were 100, 86.7, 90, and 100%, respectively. Combined with results of diatom tests of MD‐VF‐Auto SEM method, this multiplex PCR system could help rule out nondrowning bodies and provide extra evidences to support drowning diagnosis, especially for those cases with few diatoms observed. It is expected that this multiplex PCR system has great potential for forensic drowning diagnosis.

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Analysis of false-positive results of diatom test in the diagnosis of drowning—would not be an impediment

Cited by 25 publications

References 12 publications

Diagnosis of Drowning and the Value of the Diatom Test in Veterinary Forensic Pathology

Diagnosis of Drowning and the Value of the Diatom Test in Veterinary Forensic Pathology

Research advances in forensic diatom testing

Development and application of a multiplex PCR system for drowning diagnosis

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