Forensic Sci Int 2014 May 18;238:120-4. Epub 2014 Feb 18.
Institute of Forensic Medicine, Rheinische Friedrich-Wilhems-University, Bonn, Germany.
There is a need for quick and reliable methods for rapid screening of drug-influenced drivers on the roadside by police. Because the window of detection in oral fluid is more similar to blood than to urine, this matrix should therefore be appropriate for screening procedures. The performance of the Rapid STAT(®) (Mavand Solution GmbH, Mössingen, Germany), DrugWipe5/5+(®) (Securetec Detektions-Systeme AG, Brunnthal, Germany) and Dräger DrugTest(®) 5000 (Draeger Safety AG & Co. KGaA, Luebeck, Germany) on-site oral fluid devices was evaluated with random oral fluid specimens from car drivers in North Rhine-Westphalia (Germany). Additionally, some drivers were checked using an on-site urine device (DrugScreen(®), NAL von Minden, Regensburg, Germany). During a 11-month period, 1.212 drivers were tested. Both OF and urine on-site tests were compared to serum results. The following sensitivities were obtained by the oral fluid devices: THC 71% (DrugWipe(®)), 87% (Dräger), 91% (RapidSTAT); opiates 95% (Dräger), 100% (DrugWipe(®), RapidSTAT(®)); amphetamine 84% (DrugTest(®) 5000), 90% (RapidSTAT(®)), 100% (DrugTest(®) 5000); methamphetamine 50% (DrugTest(®) 5000), 100% (RapidSTAT(®)); cocaine 76% (DrugTest(®) 5000), 100% (DrugWipe(®), RapidSTAT(®)); methadone 33-63%, and benzodiazepines 0-33% (both with a low number of positives). THC specificity was especially low (29% [DrugWipe(®)] and 47% [DrugTest(®) 5000]) due to low cut-off concentrations. These data were similar to those obtained from the literature (e.g., DRUID project). The urine screening device showed a good sensitivity (THC 93%, opiate 94%, amphetamine 94%, methamphetamine 75% (low number of positives), cocaine 100%) and also an acceptable specificity (39%, 86%, 63%, 77%, 47%, respectively). Although oral fluid may be a useful matrix for on-site testing of drugged drivers, it is evident that oral fluid devices still show a lack of sensitivity (methamphetamine, benzodiazepines) and specificity (THC). Poor results for benzodiazepines may be explained by the small positive test number. Although the sensitivity for THC came out higher than compared to the literature, specificity is not yet satisfactory (only <90%). Furthermore, specificity was poor due to lowered cut-offs resulting in multiple false positive tests.