HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS REGISTER		Author Keyword(s) Vol Page [Advanced]

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this link to a friend Similar articles in this journal Similar articles in PubMed Add article to my folders Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jones, A W Articles by Holmgren, P Search for Related Content PubMed PubMed Citation Articles by Jones, A W Articles by Holmgren, P Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB ETHANOL

Uncertainty in estimating blood ethanol concentrations by analysis of vitreous humour

¹ Department of Forensic Toxicology, University Hospital, SE-581 85 Linköping, Sweden

Professor Jones wayne.jones{at}RMV.se Aims—To determine the concentrations of ethanol in femoral venous blood (FVB) and vitreous humour (VH) obtained during forensic necropsies. The ratios of ethanol concentrations in VH and FVB, the reference interval, and the associated confidence limits were calculated to provide information about the uncertainty in estimating FVB ethanol concentrations indirectly from that measured in VH.

Methods—Ethanol concentrations were determined in specimens of FVB and VH obtained from 706 forensic necropsies. The specimens were analysed in duplicate by headspace gas chromatography (HS-GC), with a precision (coefficient of variation) of 1.5% at a mean ethanol concentration of 500 mg/litre. The limit of detection of ethanol in body fluids by HS-GC in routine casework was 100 mg/litre.

Results—In 34 instances, ethanol was present in VH at a mean concentration of 154 mg/litre, whereas the FVB ethanol concentration was reported as negative (< 100 mg/litre). These cases were excluded from the statistical analysis. The concentration of ethanol in FVB was higher than in VH in 93 instances, with a mean difference of 160 mg/litre (range 0 to 900). The mean concentration of ethanol in FVB (n = 672) was 1340 mg/litre (SD, 990) compared with 1580 mg/litre (SD, 1190) in VH. The arithmetic mean VH/FVB ratio of ethanol was 1.19 (SD, 0.285) and the 95% range was 0.63 to 1.75. The mean and SD of the differences (log VH - log FVB) was 0.063 (SD, 0.109), which gives 95% limits of agreement (LOA) from -0.149 to 0.276. Transforming back to the original scale of measurement gives a geometric mean VH/FVB ratio of 1.16 and 95% LOA from 0.71 to 1.89. These parametric estimates are in good agreement, with a median VH/FVB ratio of 1.18 and 2.5th and 97.5th centiles of 0.63 and 1.92.

Conclusions—The ethanol distribution ratios (VH/FVB) show wide variation and this calls for caution when results of analysing VH at necropsy are used to estimate the concentration in FVB. Dividing the ethanol concentration in VH by 2.0 would provide a very conservative estimate of the ethanol content in FVB, being less than the true value, with a high degree of confidence.

Key Words: analysis • blood • ethanol • vitreous humour

This article has been cited by other articles:

				A W Jones and F C Kugelberg Alcohol concentrations in post-mortem body fluids Human and Experimental Toxicology, November 1, 2006; 25(11): 623 - 624. [PDF]

				B S De martinis, C M. de Paula, A Braga,, H T Moreira, and C C. Martin Alcohol distribution in post-mortem fluids Human and Experimental Toxicology, November 1, 2006; 25(11): 625 - 626. [PDF]

				B S De Martinis, C M. de Paula, A Braga, H T Moreira, and C C. Martin Alcohol distribution in different postmortem body fluids Human and Experimental Toxicology, February 1, 2006; 25(2): 93 - 97. [Abstract] [PDF]

				M A Parsons, R D Start, and A R W Forrest Concurrent vitreous disease may produce abnormal vitreous humour biochemistry and toxicology J. Clin. Pathol., September 1, 2003; 56(9): 720 - 720. [Full Text] [PDF]