title: An evaluation of the DRI-ETG EIA method for the determination of ethyl glucuronide concentrations in clinical and post-mortem urine.
abstract: A commercial enzyme immunoassay for the qualitative and semi-quantitative measurement of ethyl glucuronide (EtG) in urine was evaluated. Post-mortem (n=800), and clinical urine (n=200) samples were assayed using a Hitachi 902 analyzer. The determined concentrations were compared with those obtained using a previously published liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of EtG and ethyl sulfate. Using a cut-off of 0.5 µg/ml and LC-MS/MS limit of reporting of 0.1 µg/ml, there was a sensitivity of 60.8% and a specificity of 100% for clinical samples. For post-mortem samples, sensitivity and specificity were 82.4% and 97.1%, respectively. When reducing the cut-off to 0.1 µg/ml, the sensitivity and specificity were 83.3% and 100% for clinical samples whereas for post-mortem samples the sensitivity and specificity were 90.3 % and 88.3 %, respectively. The best trade-offs between sensitivity and specificity for LC-MS/MS limits of reporting of 0.5 and 0.1 µg/ml were achieved when using immunoassay cut-offs of 0.3 and 0.092 µg/ml, respectively. There was good correlation between quantitative results obtained by both methods but analysis of samples by LC-MS/MS gave higher concentrations than by enzyme immunoassay (EIA), with a statistically significant proportional bias (P<0.0001, Deming regression) for both sample types. The immunoassay is reliable for the qualitative and semi-quantitative presumptive detection of ethyl glucuronide in urine.
authors.affiliation: Victorian Institute of Forensic Medicine, Southbank, Victoria, Australia. sophiet@vifm.org
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Turfus
authors.forename: Tu
authors.initials: T
authors.lastname: Vo
authors.forename: Nadia
authors.initials: N
authors.lastname: Niehaus
authors.forename: Dimitri
authors.initials: D
authors.lastname: Gerostamoulos
authors.forename: Jochen
authors.initials: J
authors.lastname: Beyer
mesh_terms: D019973:Alcohol-Related Disorders / Q000652:urine*; D001344:Autopsy; D002853:Chromatography, Liquid / Q000379:methods; D005554:Forensic Medicine; D005965:Glucuronates / Q000652:urine*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D005965:Glucuronates; C093924:ethyl glucuronide