Swiss researchers have found a new way to detect the date-rape drug GHB in urine for up to 72 hours after it is taken, a development that could help sexual assault investigations. The University of Zurich said in a statement published on Tuesday that the newly identified biomarker may show earlier GHB intake even when the drug can no longer be found using standard analysis.
The university stressed how time-sensitive these cases are. “Every hour is critical when it comes to detecting the use of drugs used to render victims unconscious,” the statement said. GHB, which is often slipped into drinks without victims noticing, is cleared quickly from blood and urine. The university said the usual detection window is around six hours in blood and 12 hours in urine.
Biomarker first identified by a team in 2021
A team led by Andrea Steuer at the university’s Institute of Forensic Medicine helped discover a promising biomarker for the drug in 2021. Known as GHB-pentose, the compound combines GHB with a sugar thought to be ribose. Unlike GHB itself, the statement said, it remains detectable in urine for longer after intake.
The study found the compound stayed detectable for up to three days after GHB intake, which the university described as the longest detection window reported for a direct GHB-related biomarker to date.
Analysis of 2,414 forensic urine samples
For the study, published last week in the peer-reviewed journal Drug Testing and Analysis, the researchers examined 2,414 anonymised urine samples from genuine forensic cases since 2024. In 14 samples, GHB levels were below the test threshold, yet GHB-pentose was still detected.
In eight of those 14 cases, the case details supported the suspicion that GHB had been taken or administered earlier. These included three suspected criminal offences: two robberies and one alleged sexual assault, where urine samples were collected only 13 to 16 hours after the incident.
Steuer said the findings provide the first sign from forensic practice that GHB-pentose remains detectable beyond the usual window for GHB.
Limits of the method still under review
The researchers described the results as promising but said they do not yet show how reliable the method is for diagnosis in individual cases. They also said the maximum detection period in any single case has not been determined.
