Endogenous level and in vitro production of GHB in blood from healthy humans, and the interpretation of GHB levels detected in antemortem blood samples

Abstract

The endogenous level of γ-hydroxybutyric acid (GHB) and the in vitro production of GHB in blood from healthy humans have been investigated. The endogenous GHB concentrations in aseptically collected whole blood samples ranged from 5 to 10 ng/ml, which were far below the previously-reported "endogenous" levels . Also, the levels of in vitro GHB production during storage for 16 months at 4°C were lower than 0.4 μg/ml, which were much lower than those in postmortem samples previously reported. Based on the results of this investigation, the authors concluded that an interpretative cutoff of 1.0 μg/ml would be appropriate for differentiating exogenous from endogenous GHB, if only limited to in-life blood specimens that were collected aseptically, stored at 4°C or lower, examined within two weeks, and excludes the possibility of GHB aciduria.