title: An enzymatic method to determine γ-hydroxybutyric acid in serum and urine.
abstract: BACKGROUND
  Gamma-hydroxybutyric acid (GHB) has become one of the most dangerous illicit drugs of abuse today. It is used as a recreational and date rape drug because of its depressant effect on the central nervous system, which may cause euphoria, amnesia, respiratory arrest, and coma. There is an urgent need for a simple, easy-to-use assay for GHB determination in urine and blood. In this article, a rapid enzymatic assay adapted to clinical chemistry analyzers for the detection of GHB is presented.
  
  
  METHODS
  The described GHB enzymatic assay is based on a recombinant GHB dehydrogenase. The full validation of the assay was performed on a Konelab 30 analyzer (Thermo Fisher Scientific).
  
  
  RESULTS
  The analytical sensitivity was <1.5 mg/L, whereas the functional sensitivity was 4.5 mg/L in serum and 2.8 mg/L in urine. The total imprecision coefficient of variation (CV) was <9.8% in serum and <7.9% in urine. The within-run imprecision showed a CV of <3.8% in serum and <4.6% in urine. The assay was linear within the range 5-250 mg/L. Mean recoveries were 109% in serum and 105% in urine. No cross-reactivity was observed for tested GHB analogues and precursors. Comparison of GHB-positive samples showed an excellent correlation with ion chromatography, gas chromatography-mass spectrometry, and liquid chromatography associated to tandem mass spectrometry. Except for ethanol, no substantial interference from serum constituents and some drugs was observed.
  
  
  CONCLUSIONS
  This automated GHB assay is fully quantitative and allows the accurate measurement of GHB in serum and urine. It can be used as a rapid screening assay for the determination of GHB in intoxicated or overdosed patients.
authors: Bühlmann Laboratories AG, Schoenenbuch, Switzerland.
authors: Lara
authors: L
authors: Hasan
authors: Thomas M
authors: TM
authors: Jermann
authors: Jakob M
authors: JM
authors: Weber
authors: Lars
authors: L
authors: Abrahamsson
authors: Michel-Angelo
authors: MA
authors: Sciotti
authors: Michael
authors: M
authors: Böttcher
authors: Wolfgang
authors: W
authors: Jöchle
authors: Daniel
authors: D
authors: Gygax
authors: André
authors: A
authors: Scholer
mesh_terms: D057205:Automation, Laboratory; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002138:Calibration; D002492:Central Nervous System Depressants / Q000097:blood / Q000652:urine; D020118:Cupriavidus necator / Q000201:enzymology; D004355:Drug Stability; D006801:Humans; D006884:Hydroxybutyrate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D006885:Hydroxybutyrates / Q000097:blood* / Q000652:urine*; D013287:Illicit Drugs / Q000097:blood* / Q000652:urine*; D057230:Limit of Detection; D011994:Recombinant Proteins / Q000378:metabolism; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D002492:Central Nervous System Depressants; D006885:Hydroxybutyrates; D013287:Illicit Drugs; D011994:Recombinant Proteins; C111420:4-hydroxybutyric acid; D006884:Hydroxybutyrate Dehydrogenase; C019416:4-hydroxybutyrate dehydrogenase