Researchers at the University of Zurich have identified a new biomarker that makes it possible to detect the presence of GHB—often referred to as the “date-rape drug”—in urine up to 72 hours after consumption, thereby significantly extending the detection window for this substance.
“The typical detection window is approximately six hours in the blood and twelve hours in the urine,” explains a research team led by Dr. Andrea Steuer at the University of Zurich’s Institute of Forensic Medicine. They emphasise that, given current detection methods, every hour counts when identifying this drug—a substance often used to render victims unconscious.
In 2021, the research team identified a new biomarker: a compound formed by gamma-hydroxybutyrate (GHB) and sugar, known as GHB-pentose.
“Unlike GHB itself, this biomarker remains detectable in urine for a longer period following ingestion,” the statement notes.
In a study published on Tuesday, the researchers analysed 2,414 anonymised urine samples taken from actual forensic case files between 2024 and 2026.
During this testing, 14 samples proved “particularly useful”: while the measured GHB levels fell below the established analytical threshold, GHB-pentose was still detected, the statement explains.
“In eight of these cases, details from the files supported the suspicion that GHB had been consumed or administered,” the statement adds.
“These included three alleged criminal offenses—two robberies and one alleged sexual assault—in which the urine samples were collected 13 to 16 hours after the incident,” the statement continues.
Their findings demonstrate that this biomarker can indicate prior GHB use, even when the substance itself is no longer detectable through conventional analytical methods. On its website, the Swiss Federal Office of Public Health explains that GHB is an “ideal candidate” for malicious use.
It is a substance that is “virtually odorless” and “water-soluble,” meaning it can “go unnoticed in a drink.” It produces “an euphoric effect that manifests very quickly—within as little as 15 minutes—and progresses to a state of fatigue.” Upon waking, victims often have no memory of what happened to them, the ministry notes.
