Abstract: Objective To compare the efficacy of three methods for forensic diatom test, namely strong acid digestion-centrifuge
enrichment-light microscopy (SD-CE-LM), microwave digestion-membrane filtration-automated scanning electron microscopy
(MD-ME-SEM), and microwave digestion-membrane filtration-light microscopy (MD-MF-LM). Methods Sixty samples were
randomly divided into 3 groups for diatom test using three methods, and the sample preparation time, degree of digestion and
recovery rate of diatoms were compared. Results The sample preparation time was the shortest with MD-MF-LM and the
longest with SD-CE-LM (P<0.05). MD-ME-SEM and MD-MF-LM allowed more thorough tissue digestion than SD-CE-LM.
MD-ME-SEM resulted in the highest total recovery rate of diatom, followed by MD-MF-LM and then by SD-CE-LM (P<0.05);
the recover rate of different diatom species was the highest with MD-ME-SEM, followed by MD-MF-LM and SD-CE-LM (P<
0.05). Conclusion SD-CE-LM has a low recovery rate of diatoms especially for those with lengths shorter than 40 μm or
densities less than 1/5. With a high recovery rate and accuracy in diatom test, MD-ME-SEM is suitable for diagnosis of
suspected drowning cases. MD-MF-LM is highly efficient, sensitive and convenient for forensic diatom test.