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Post-mortem formation of GHB: A retrospective study of forensic autopsies
Marit Årnes1, Hilde Marie Erøy Edvardsen2, Line Berge Holmen3
1Oslo University Hospital, Department of Forensic Sciences, Oslo, Norway; Center for Psychopharmacology, Diakonhjemmet Hospital, Oslo, Norway.
Aims:
The aims were to investigate the occurrence of post-mortem formation of gammahydroxybutyrate (GHB) at different GHB blood concentration levels, the urine/blood ratios seen after post-mortem formation of GHB, and how often ethanol was co-formed with GHB.
Methods:
Our study includes 525 cases with GHB concentrations above 31.2 mg/L in blood and urine. The results were linked to the Norwegian Cause of Death Registry. We set a ratio below two between urine and blood GHB concentration as indicator for postmortem formation of GHB, and used data regarding official causes of death to verify the classification. Post-mortem formed ethanol was defined as positive ethanol combined with negative ethyl sulfate (EtS) results.
Results:
Of all GHB positive cases, 85 % were defined as post-mortem formation, with a median urine/blood ratio of 0.52. The majority were lower concentrations, but 30 % of the cases showed GHB blood concentrations above approximately 50 mg/L (500 micromol/L). In the cases with urine/blood ratio above two, intake of GHB was suspected, and 15 % of these had GHB concentration in blood below approximately 50 mg/L. Co-formation of ethanol was seen in 27 % of cases with post-mortem formed GHB. The post-mortem interval (PMI) was significantly longer in cases with post-mortem formed GHB and ethanol.
Conclusions:
GHB in post-mortem cases is most commonly formed after death, and concentrations are mainly, but not exclusively, in lower levels. Co-formation of ethanol occurs in about 30 % of cases, and increasing PMI increase the frequency of post-mortem formation of GHB and ethanol.
