Preferred Sample Type

Gamma hydroxybutyrate (GHB)

Suitable Specimen Types

  • Plain Spot Urine
  • Fluoride Oxalate
100 ul urine/plasma

Specimen Transport


Sample Processing in Laboratory

Inform toxicology when samples arrive

Sample Preparation


Turnaround Time

3 days.

Sample Stability

Store frozen.

Gamma hydroxybutyrate (GHB)

General Information

Gamma-hydroxybutyrate (GHB also known as 4-hydroxybutyric acid) is an endogenous metabolite, present in most mammalian tissues at nanomolar concentrations, that has been hypothesized to have a role as a neurotransmitter and is a metabolite of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). It may be employed clinically as an anaesthetic and hypnotic agent, however GHB is used illicitly both as a steroid alternative for body building and also  as a ‘club’ or ‘date rape’ drug due to its hypnotic effect and lack of colour or odour. Euphoria, increased sex drive, and tranquillity are reported positive effects of GHB abuse. Negative effects may include sweating, loss of consciousness (reported by 69 percent of users), nausea, hallucinations, amnesia, and coma, among other adverse effects. Several metabolic precursors to GHB, such as gamma-butyrolactone (GBL) and 1,4-butanediol, and GBL analogues such as gamma-valerolactone (GVL), have also been subject to abuse. GHB, either as the primary agent or as a metabolite of GBL or 1,4-butanediol, may therefore be measured when there is a question as to whether a drink may have been spiked. However, GHB is metabolised quickly with the drug undetectable in urine 12 hours post dose. This assay will not detect GVL use.

Patient Preparation

GHB is cleared from the body very quickly and is often undetectable in urine 12 h post dose. Please take samples (urine and blood if possible) as soon as possible following potential exposure.


Analysed by GC-MS.

Reference Range

Gamma-hydroxybutyrate (GHB) has been employed as an anaesthetic agent but is now more widely used and abused for its sedative properties. Toxic effects (euphoria, dizziness and unconsciousness) usually occur around 15 minutes post ingestion and last on average for about 3 hours. It has been found that blood concentrations above 260 mg/L were associated with deep sleep, 156 – 260 mg/L with moderate sleep, 52 – 156 mg/L with light sleep and levels less than 52 mg/L with wakefulness.



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The Trust Laboratories at Heartlands Hospital, Good Hope Hospital and Solihull Hospital were awarded UKAS (United Kingdom Accreditation Service) accreditation to the internationally recognised ISO 15189 standard in May 2015. For a list of accredited tests and other information please visit the test database
Tests not appearing on this scope are either under consideration or in the process of accreditation and so currently remain outside of our scope of accreditation. However, these tests have been validated to the same high standard as accredited tests and are performed by the same trained and competent staff.

For further information contact Louise Fallon, Quality Manager, 0121 424 1235