The Diagnostic Value of Quantitative Assessment of Diatom Test for Drowning: An Analysis of 128 Water‐related Death Cases using Microwave Digestion‐Vacuum Filtration‐Automated Scanning Electron Microscopy

Abstract

The value of diatom test for the diagnosis of drowning remains controversial. The conventional forensic diatom test with low sensitivity is not a useful tool to provide accurate information about diatom in the tissues and organs. To improve the sensitivity of the diatom test, we developed a novel method called the Microwave Digestion-Vacuum Filtration-Automated Scanning Electron Microscopy (MD-VF-Auto SEM) method which resulted in a high recovery of diatoms. In this article, we analyzed 128 water-related death cases. Our results showed that the MD-VF-Auto SEM method could achieve a much higher positive rate (0.97) in drowning cases. Large amounts of diatoms are retained, even concentrated, in the lung tissues during the intense breathing movement in drowning process. This might be useful for the diagnosis of drowning. Our research indicates that the MD-VF-Auto SEM method would be a valuable methodology in the study of diatom test for the forensic community.

Investigation of Drowning Deaths: A Practical Review

“…Contamination leading to false positives for the presence of diatoms that could lead to a misdiagnosis also remains one of the issues of concern cited by researchers (70). With the development of more streamlined extraction methods with shorter turnaround-times and overall higher sensitivity and specificity, the successful recovery of diatoms from a variety of tissues and fluids (lung, liver, kidney, bone marrow, and cavity fluid) along with comparison to that found in the drowning medium has been shown to be an occasionally useful adjunct to not only the diagnosis of drowning but also in the ruling out of drowning as the cause of death (70, 71, 103, 104). That being said, due to the various difficulties discussed, diatom examination is not considered standard of practice when investigating potential water-related deaths.…”

Research advances in forensic diatom testing

“…The result shows that the MD-VF-Auto SEM method can provide supporting evidence to identify the reason why a corpse was in water. In 2017, this team analyzed the sensitivity and detection rate of 128 drowning cases that used this method [12]. The detection rate was 100% in lung tissue samples and 97% in distant organ samples (such as the liver or kidney); these results illustrated that the MD-VF-Auto SEM method can effectively improve the diatom detection rate in a corpse.…”

Dead in the water: Epilepsy‐related drowning or sudden unexpected death in epilepsy?

“…The diatom test detects a phytoplankton aspirated from the water and identified in the decedent's lungs or stomach . Although current diatom tests have increased sensitivity and specificity, they still are based on small case series and suffer from potential antemortem contamination as well as false‐positive results that limit its diagnostic validity . “Dry drowning,” with no significant aspiration of fluid, results from laryngeal spasm after the contact of the liquid with the oropharyngeal airways, but there is no clear definition of “dry lung.” Combined lung weight <1000 g is usually accepted as normal, but seizures and agonal processes can cause pulmonary edema and increase lung weight without drowning .…”