GHB biomarker may reveal use for up to 72 hours

Swiss researchers say a newly studied urine biomarker could help detect use of the drug GHB for up to 72 hours after intake, potentially extending the testing window in sexual assault and other criminal investigations.

The University of Zurich said the biomarker, known as GHB-pentose, could indicate earlier GHB intake even when the drug is no longer detectable by conventional analysis. It said usual detection windows are about six hours in blood and 12 hours in urine.

A team led by Andrea Steuer at the university's Institute of Forensic Medicine analysed 2,414 anonymised urine samples from forensic cases since 2024 for a study published in the peer-reviewed journal Drug Testing and Analysis.

The researchers highlighted 14 samples in which GHB levels were below the test threshold but GHB-pentose was still detected. The university said case details in eight of those 14 cases supported suspicion that GHB had been taken or administered earlier, including three suspected criminal offences: two robberies and one alleged sexual assault.

Steuer said the findings offered the first indication from forensic practice that GHB-pentose remains detectable beyond the usual window for GHB. The researchers said the results do not yet establish the method's diagnostic reliability or the maximum detection period in an individual case.