ZURICH, Nov 11 — Swiss researchers have found a new way of detecting renowned date-rape drug GHB in urine for up to 72 hours after ingestion, in a possible boon to sexual assault investigations.

The University of Zurich said in a statement published Tuesday that the newly discovered biomarker could “indicate earlier GHB intake even when the drug is no longer detectable using conventional analysis”.

“Every hour is critical when it comes to detecting the use of drugs used to render victims unconscious,” it said.

But GHB, which is commonly used for this purpose, including by being slipped into drinks of unsuspecting victims, is excreted rapidly from blood and urine, leaving little time to test for it before all traces vanish.

“The usual detection window is around six hours in the blood and 12 in the urine,” Zurich University pointed out.

A team led by Andrea Steuer at the university’s Institute of Forensic Medicine had in 2021 helped discover a “promising biomarker” for the drug — a compound of GHB and a sugar thought to be ribose, known as GHB-pentose.

“Unlike GHB itself, this biomarker remains detectable in the urine for longer after intake,” the statement said.

The study indicated that the compound “remained detectable for up to three days after GHB intake, representing the longest detection window reported for a direct GHB-related biomarker to date”.

For their study published last week in the peer-reviewed scientific journal Drug Testing and Analysis, the researchers analysed 2,414 anonymised urine samples from genuine forensic cases since 2024.

Highlighting 14 samples, the researchers found that “although GHB levels measured were below the threshold set for the test, GHB-pentose was still detected”.

“In eight of these 14 cases, the case details supported the suspicion that GHB had been taken or administered previously,” the statement said.

Those cases included three suspected criminal offences — two robberies and one alleged sexual assault, in which urine samples were only gathered 13-16 hours after the incident.

“The findings offer the first indication from forensic practice that GHB-pentose remains detectable beyond the usual detection window for GHB,” Steuer said in the statement.

While promising, the researchers said the findings did not yet make it possible to determine the diagnostic reliability or the maximum detection period in any individual case using the method. — AFP