Researchers at the University of Zurich have demonstrated that a newly evaluated biomarker may help forensic laboratories detect previous exposure to gamma-hydroxybutyrate (GHB), even when conventional toxicology tests no longer detect the substance.
The findings, published in Drug Testing and Analysis in November 2026, could improve investigations involving suspected drug-facilitated crimes and unexplained deaths.
GHB is a central nervous system depressant that can cause sedation, impaired consciousness and memory loss. It is sometimes administered without a person's knowledge during criminal offences.
Detecting GHB presents a significant challenge because the substance is rapidly eliminated from the body. Conventional testing generally offers detection windows of approximately six hours in blood and 12 hours in urine.
GHB also occurs naturally in small quantities in the human body, complicating interpretation.
Researchers investigated GHB-pentose, a compound formed through the association of GHB with a sugar molecule, believed to be ribose. Its exact chemical structure has not yet been conclusively established.
Earlier controlled research indicated that GHB-pentose could remain detectable in urine for up to three days after GHB consumption.
To evaluate its usefulness in actual forensic investigations, the researchers examined 2,414 anonymized urine samples collected from cases between 2024 and 2026.
They used two independent liquid chromatography–tandem mass spectrometry methods to identify the biomarker.
GHB-pentose was detected in all 21 GHB-positive urine samples obtained from living individuals.
More importantly, researchers identified 14 samples in which GHB concentrations were below the laboratory's reporting threshold, but GHB-pentose remained detectable.
Case information supported previous GHB exposure in eight of these instances.
Three involved suspected criminal offences, including two robberies and an alleged sexual assault. Samples from these investigations had been collected approximately 13 to 16 hours after the incidents.
The findings suggest that GHB-pentose may provide additional evidence of exposure when delayed sample collection limits conventional testing.
Researchers also investigated whether the biomarker could help distinguish GHB consumed before death from GHB formed naturally during decomposition.
Among 20 postmortem urine samples with elevated GHB concentrations, GHB-pentose was absent. Four additional postmortem samples contained both compounds.
These observations suggest that the biomarker may assist in interpreting GHB findings during death investigations.
However, the results do not establish a universally reliable detection period or prove that every positive biomarker result represents criminal administration.
The study also does not establish definitive diagnostic sensitivity and specificity across all forensic conditions.
Despite these limitations, the researchers demonstrated that GHB-pentose analysis can be incorporated into existing laboratory methods, even though a commercial reference standard is not yet available.
The University of Zurich reports that its forensic laboratory now routinely examines GHB-pentose when GHB administration is suspected.
The findings represent a promising advance in forensic toxicology, particularly for investigations where delayed reporting or sample collection may otherwise leave little detectable evidence of drug exposure.