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Immunochromatographic rapid tests for drugs-of-abuse testing in urine have been developed by many pharmaceutical manufacturers.
Materials:
Nine different commercially available rapid tests for detecting benzodiazepines, amphetamines and methamphetamines in urine were compared (Boehringer Frontline, Syva Rapid Test, Biosite Triage, Roche Ontrak Teststik (amphetamines only), Forefront Instacheck , D.S.S.I. microline Screen, Bionike/Biomar ToxiQuick, Syntron/von Minden, PBM/Mahsan).
Method:
The following commonly prescribed benzodiazepines or their forensically relevant metabolites (Alprazolam, Bromazepam, 7-Amino-Clonazepam, Desalcylflurazepam, 7-Amino-Flunitrazepam, 7-Amino-Nitrazepam, Nordazepam, Triazolam) were added to drug-free urine to obtain samples containing benzodiazepines in different concentrations above and below the cut-off concentration of 300 ng/mL indicated by the manufacturers. The same procedure was used to test for amphetamine, methamphetamine, MDMA, MDEA, MDA, MBDB, ephedrine, phenylethyl-amine, tyramine and phenylpropanolamine. Finally 40 samples of real material were tested by Boehringer and Bionike with confirmation by HPLC.
Results:
The limits of detection (LOD) of the compared rapid tests vary considerably, but Boehringer Frontline and Bionike/Biomar ToxiQuick reached the lowest LOD with an average benzodiazepine concentration of 25 ng/mL. The Boehringer Frontline had no false positive results and the Bionike had just one false positive out of 20 samples confirmed negative by the highly sensitive HPLC method. The Roche Ontrak Teststik was positive only for amphetamine. Biosite Triage showed the highest rate of interference with phenylethylamine and tyramine, the metabolites of putrefaction. |
