Evaluation of an onsite alcohol testing device for use in postmortem forensic toxicology

The disposable QED saliva alcohol test provides a very simple, fast, and reliable means for quantitative onsite alcohol detection. The purpose of this study was to determine if the QED test would be a useful tool for the determination of postmortem ethanol levels in cases where a rapid result was needed. QED results were compared with ethanol levels determined by headspace GC analysis. Both saliva and vitreous humor specimens were used for the evaluation. QED tests were initially attempted using the oral fluid from 50 individuals. Of these cases, 17 of the tests were valid with 8 positive results. For 23 cases the oral fluid was not attainable, and for 10 cases, the sample was contaminated with blood making the tests invalid. The correlation between the oral fluid results and the blood headspace GC analysis was poor (r = 0.8345) over the range of 0.01-0.29 g/dL. Vitreous specimens were found to be the matrix of choice for analyzing postmortem cases using the QED. Only 6 of 171 specimens were found to be unsuitable. The QED results correlated well with the headspace GC analysis (r = 0.9931, n = 165). When using ethanol levels > 0.02 g/dL (n = 126), an average vitreous (GC)/blood ratio of 1.16 correlated well with the average QED/blood ratio of 1.22. Although the QED saliva alcohol test does not appear to be useful in determining postmortem saliva ethanol levels, it does provide accurate results when using postmortem vitreous humor as the testing matrix.