Swiss researchers find new way to detect date rape drug GHB for up to 72 hours. Here's how it works

Researchers at the University of Zurich have identified a new way of detecting the date-rape drug GHB in urine for up to 72 hours after ingestion, a finding that could give investigators far more time to build sexual assault cases. The university said in a statement published Tuesday (Nov 10) that the newly discovered biomarker could "indicate earlier GHB intake even when the drug is no longer detectable using conventional analysis". It added: "Every hour is critical when it comes to detecting the use of drugs used to render victims unconscious."

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The usual window lets perpetrators get away; that's about to change

GHB is commonly used to render victims unconscious, often by being slipped into the drinks of unsuspecting victims. The so-called date rape drug is excreted rapidly from blood and urine, leaving little time to test for it before all traces vanish. The university pointed out that "the usual detection window is around six hours in the blood and 12 in the urine."

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.

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What the study found

The study indicated 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 the research, published last week in the peer-reviewed journal Drug Testing and Analysis, the team 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 those 14 cases, the case details supported the suspicion that GHB had been taken or administered previously. Those cases included three suspected criminal offences, two robberies and one alleged sexual assault, in which urine samples were only gathered 13 to 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 allow them to determine the diagnostic reliability or the maximum detection period for any individual case using the method.