Urinary γ-hydroxybutyrate concentrations in 1126 female subjects

Area of Science:

• Forensic Toxicology
• Analytical Chemistry

Background:

• Gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) are frequently linked to drug-facilitated sexual assault (DFSA).
• Confirming GHB/GBL ingestion is challenging due to GHB's natural presence in the body and rapid excretion.
• A urinary discriminant limit of 10 mg/L is often used to indicate GHB/GBL consumption.

Purpose of the Study:

• To develop and validate a rapid gas chromatography-mass spectrometry (GC-MS) method for GHB analysis in urine.
• To analyze GHB concentrations in a large cohort of women to support existing discriminant limits.

Main Methods:

• A rapid GC-MS method was developed for GHB analysis after conversion to GBL.
• Urine samples from 1126 women were analyzed for GHB concentrations.
• Statistical analysis was performed to assess the influence of pH, age, BMI, race, and specific gravity on GHB levels.

Main Results:

• GHB concentrations in urine were independent of urinary pH, age, BMI, and race.
• Adjusting for urinary specific gravity had minimal impact on mean GHB values.
• A statistically significant trend showed increasing GHB with higher specific gravity.

Conclusions:

• The findings provide further support for the established 10 mg/L urinary discriminant limit for GHB administration in antemortem samples.
• The validated GC-MS method offers a reliable tool for GHB detection in forensic toxicology.
• Understanding GHB pharmacokinetics and influencing factors is crucial for accurate interpretation of forensic results.