Evaluation of KIMS immunoassays on a cobas c 501 analyzer for drugs of abuse and ethyl glucuronide testing in urine for forensic abstinence control

Abstract

For the medico-psychological assessment (MPA) during driving licence re-granting in Germany, abstinence control including urine samples is required. In these programmes, even small amounts of markers for drug or alcohol abuse have to be detected. Thus, the concentrations of the target compounds are very low, and, in consequence, the sensitivity of the applied screening method has to be much higher than for clinical use. Modified drugs of abuse and ethyl glucuronide immunoassays on a Roche cobas c 501 analyzer were evaluated for precision, accuracy, onboard calibration stability, cross reactivity, sensitivity, and specificity using authentic urine samples. Precision (intra-day and inter-day relative standard deviation (RSD) and accuracy (bias) at three concentrations were 12% or lower for all parameters. The calibrations remained stable (deviations <25%) for at least 28 days for all assays except amphetamines (21 days). Satisfactory cross reactivity was determined for the relevant analytes and also for several new psychoactive substances (NPS). The sensitivity was 100% for all parameters except methadone metabolite EDDP (92%) and fully met the sensitivity criteria for MPA urine testing. The presented kinetic interaction of microparticles in a solution (KIMS) immunoassays on a cobas c 501 thus provide a new method to reliably detect drug or alcohol consumption in abstinence control programmes requiring high sensitivity. Copyright © 2016 John Wiley & Sons, Ltd.

Sensitive determination of ethyl glucuronide in serum and whole blood: detection time after alcohol exposure compared with urine

“…Ethyl glucuronide (EtG) is a direct, minor metabolite of ethanol that is routinely used as a biomarker for recent drinking. EtG measurement has become an established complementary parameter in urine drug testing and commercial immunochemical screening tests are available [1,2]. To secure a preliminary positive immunoassay EtG result, mass spectrometry (MS) methods are used and often include also measurement of ethyl sulfate (EtS), another conjugated ethanol metabolite [3], to confirm alcohol intake [4,5].…”