Site-dependent production of γ-hydroxybutyric acid in the early postmortem period

This study compared endogenous γ-hydroxybutyric acid (GHB) concentrations in various postmortem fluid samples of 25 autopsy cases. All bodies were stored between 10-20 °C until autopsy, and the intervals between death and autopsy were less than 2 days (6-48 h). GHB concentrations were measured by headspace gas chromatography after GHB was converted to γ-butyrolactone. Endogenous GHB concentrations were significantly higher in femoral venous blood (4.6 ± 3.4 μg/ml, n = 23) than in cerebrospinal fluid (1.8 ± 1.5 μg/ml, n = 9), vitreous humor (0.9 ± 1.7 μg/ml, n = 8), bile (1.0 ± 1.1 μg/ml, n = 9) and urine (0.6 ± 1.2 μg/ml, n = 12). GHB concentrations were similar in blood samples taken from different sites. Cut-off limits of 30 and 10 μg/ml are proposed for blood and urine, respectively, to discriminate between exogenous and endogenous GHB in decedents showing no or little putrefaction (postmortem intervals usually 48 h or less). The criterion established for endogenous GHB in postmortem urine may also be applicable to analytical results in cerebrospinal fluid, vitreous humor and bile from deceased persons.