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Gamma-hydroxybutyrate in urine and serum: additional data supporting current cut-off recommendations
H Andresen1, N Sprys, A Schmoldt
1Department of Toxicology, Institute of Legal Medicine, University Medical Center Hamburg-Eppendorf, Butenfeld 34, 22529 Hamburg, Germany. h.andresen@uke.uni-hamburg.de
Forensic Science International
|April 27, 2010
Summary
This study determined endogenous Gamma-Hydroxybutyrate (GHB) levels in serum and urine. Findings confirm the current serum cutoff and propose a new urine cutoff to improve detection in drug-facilitated crime cases.
Area of Science:
- Forensic Toxicology
- Analytical Chemistry
Background:
- Gamma-Hydroxybutyrate (GHB) is used recreationally and in drug-facilitated crimes.
- GHB's short half-life and endogenous presence complicate detection, especially in delayed samples.
- Distinguishing exogenous from endogenous GHB is crucial for accurate forensic interpretation.
Purpose of the Study:
- To quantify endogenous GHB levels in human serum and urine.
- To establish reliable cutoff concentrations for GHB detection in forensic toxicology.
- To optimize interpretation of GHB results in suspected drug-facilitated crime cases.
Main Methods:
- Gas chromatography-mass spectrometry (GC-MS) was used for GHB analysis.
- Serum and urine samples were derivatized to trimethyl-silyl derivatives prior to analysis.
- Endogenous GHB levels were determined in 100 samples (50 serum, 50 urine).
Main Results:
- Serum GHB concentrations ranged from 0.62 to 3.24 mg/L (mean 1.14 mg/L).
- Urine GHB concentrations ranged from 0.64 to 4.20 mg/L (mean 1.21 mg/L).
- The study confirmed the existing 4 mg/L lower cutoff for ante mortem serum samples.
Conclusions:
- The established serum cutoff for GHB is reliable.
- A lower cutoff of 6 mg/L for urine is proposed to reduce false negatives.
- These findings aid in the accurate interpretation of GHB in forensic investigations.
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