Accuracy of VITROS alcohol analysis for post-mortem specimens

Abstract

In forensic cases, blood alcohol is routinely requested. Although the standard method for alcohol analysis is the gas chromatographic technique, the instrument is not available in some hospital laboratories. As a result, there is an attempt to use an automatic alcohol analyzer for preliminary testing. However, a barrier to application is the putrefactive changes of post-mortem specimens that might interfere with the analysis and cause false positive results. This study aims to determine the accuracy of an automatic VITROS alcohol analysis for post-mortem specimens. Blood and urine samples were modified to putrefactive appearances and analyzed for ethanol by VITROS. The measured amounts were compared with the added ethanol amounts. The results indicated that samples with fresh hemolysis and putrefactive volatile substances gave false high ethanol results. Plasma with a high glucose content in the presence of Escherichia coli or Candida albicans did not show neo-ethanol formation. Indeed, all samples left at room temperature prior to analysis showed false low detected ethanol amounts. Thus, VITROS alcohol analysis has limitations leading to inaccurate post-mortem specimen analysis. In addition, loss of alcohol from corpses and specimen containers also has an impact on the accuracy of alcohol results in post-mortem cases. © 2014 Australian Academy of Forensic Sciences.