New biomarker may extend detection window for date-rape drug GHB
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Every hour is critical when it comes to detecting the use of drugs used to render victims unconscious. The substance GHB, which is commonly used in this way, is excreted rapidly from blood and urine. Researchers at the University of Zurich have been evaluating a new biomarker using urine samples from real forensic cases. This biomarker can indicate earlier GHB intake even when the drug is no longer detectable using conventional analysis.
Gamma-hydroxybutyrate (GHB) can be consumed as a recreational drug or administered secretly to knock victims out. Disturbed consciousness and memory gaps are just two of its effects. Its use is difficult to prove in forensic medicine, however. The usual detection window is about six hours in the blood and 12 hours in the urine. What's more, GHB occurs in small amounts naturally in the body and can also be released after death.
Promising discovery
Back in 2021, a research team led by Andrea Steuer at the Institute of Forensic Medicine at the University of Zurich, working with the University Hospital of Psychiatry Zurich, discovered a promising biomarker. It is a compound of GHB and a sugar, thought to be ribose, and is known as GHB-pentose. The exact chemical structure has not yet been established conclusively. Unlike GHB itself, this biomarker remains detectable in the urine for longer after intake.
The potential of GHB-pentose was examined in greater detail in subsequent controlled studies. A study published in 2025 showed that the biomarker can still be detected in urine for up to three days after GHB intake. It remained to be seen whether these findings would be confirmed under the varying conditions of forensic medical practice.
First reliable outcomes from clinical practice
For the study just published in Drug Testing and Analysis, the team analyzed 2,414 anonymized urine samples from genuine forensic cases from 2024 to 2026 using two independent mass spectrometry analysis methods. GHB-pentose was also found in all 21 GHB-positive urine samples from living individuals.
A further 14 samples proved particularly helpful. Although the 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. These included three suspected criminal offenses—two robberies and one alleged sexual assault—in which the urine samples were taken only 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," says last author Steuer.
Establishing GHB intake prior to death
It is also possible for GHB to form in the body after death. If the substance is detected in a deceased person, it is therefore not always clear whether it had been ingested before they died. Unlike GHB itself, GHB-pentose appears to form only after the substance has been ingested. In 20 urine samples taken from deceased individuals, the researchers found elevated levels of GHB, but no GHB-pentose. In four further samples, both substances were detectable.
"The biomarker could therefore also be helpful in investigating deaths in the future," says Steuer. Further research is still required, however.
Already usable in forensic practice
The researchers further demonstrated that GHB-pentose can be detected using two different analytical methods that are common in forensic toxicology. This means its detection can be incorporated into existing laboratory workflows, although no commercially available reference standard yet exists. "Where there is a suspicion that GHB has been administered, we now routinely test for GHB-pentose, too," Steuer notes.
The findings are promising, but do not yet allow for any final conclusion concerning diagnostic reliability or the maximum detection period in any individual case. It therefore remains crucial to assess the laboratory findings and the circumstances of each case in parallel.
Publication details
Katja Gimmler et al., Further Extensive Evaluation of GHB‐Pentose as a Novel Biomarker for the Extended Detection of GHB Intake/Administration in Forensic Casework, Drug Testing and Analysis (2026). DOI: 10.1002/dta.70183
Journal information: Drug Testing and Analysis
Key medical concepts
gamma HydroxybutyrateMass Spectrometry
Clinical categories
Laboratory medicineAllied health Provided by University of Zurich Who's behind this story?
Lisa Lock
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