|SOFT - TIAFT 1998||Poster Session 2||Wednesday October 7, 1998|
EVALUATION OF THREE IMMUNOCHROMATOGRAPHIC RAPID TESTS FOR SCREENING OF AMPHETAMINES/METHAMPHETAMINES, BENZODIAZEPINES AND COCAINE IN URINE|
Olof Beck1, Ada Goerlach-Graw2, Peter X. Iten3, Manfred Kraft*2, Manfred Moeller4, Ludwig v. Meyer5, Brian Smith6, Robert Wennig7
1Karolinska Hospital, Stockholm, Sweden;
In a number of situations a rapid analysis of drugs in urine is required. For this purpose reliable and validated tests are needed that are easy to perform without special laboratory equipment. Recently the evaluation results of three rapid assays of the Frontline® product line (Roche Diagnostics Boehringer Mannheim GmbH) for screening of drugs of abuse in urine for cannabis, opiates and cocaine have been published. This system has now been extended by a combined amphetamine/methamphetamine and by a benzodiazepine test. Furthermore the existing cocaine test has been replaced by an improved product.
In this multicenter study the rapid assays were evaluated with authentic clinical and forensic urine samples. The rapid assays were compared with immunological laboratory screening methods; in case of discrepancy between Frontline® and the comparison method a confirmation method was employed (GC-MS or HPLC).
With 309 urine samples Frontline® Amph/Methamph was compared to FPIA/GC-MS resulting in 97% sensitivity and 98% specificity at a cutoff 300 ng/ml which is mostly used in Europe and 96% sensitivity / 99% specificity at a cutoff 1000 ng/ml which is recommended by NIDA (with separate color scales for each cutoff). Synthetic drugs such as MDA, MDMA, MDE(A) and MBDB were also detected with very high sensitivity. The Frontline® test was developed for selective detection of the d-enantiomers of amphetamines/methamphetamines. This enantioselectivity resulted in lower sensitivity when compared with analytical methods that cannot distinguish between d- and l-isomers.
Preliminary results of Frontline® Benzodiazepines indicate high sensitivity with reactivities towards a broad spectrum of benzodiazepine derivatives.
Frontline® Cocaine was evaluated with altogether 921 urine samples detecting 402 of 403 positive samples (sensitivity > 99%) and finding 513 of 518 correctly negative (specificity = 99%). The 5 false positive samples contained cocaine/benzoylecgonine at a concentration only slightly below the cutoff of 300 ng/ml. The evaluation showed that the new Frontline® rapid assays gave highly reliable results.