Evaluation of two immunoassay procedures for drug testing in hair samples

A preliminary initial enzyme-linked immunosorbent assay (LUCIO (R)-Direct ELISA kit) and a preliminary DRI (R) enzyme immunoassay were evaluated for drug detection in head hair with respect to lowered cutoff values recommended in Germany for the control of abstinence in cases of re-granting of drivers' licences. Following drug classes were included: cannabinoids, opiates, cocaine like substances, amphetamine, methamphetamine (and methylenedioxyamphetamines), methadone, and benzodiazepines. 759 analyses were performed using LUCIO (R)-Direct ELISA kits and 936 analyses using DRI (R) enzyme immunoassay tests. Sample size for each drug group and immunoassay test reached from 74 to 178. The LUCIO (R)-Direct ELISA kit revealed a sensitivity of 91% for amphetamine up to 98% for methadone (methamphetamine 92%, cocaine 94%, opiates 94%, benzodiazepines 96%) and values of specificity of 72% for methadone up to 89% for amphetamine and benzodiazepines. The test was not useful for a preliminary screening for tetrahydrocannabinol (sensitivity of 65%) in consideration of a suggested cutoff of 0.02 ng/mg. The DRI (R) enzyme immunoassay test was only useful for morphine and cocaine testing at low recommended new cutoff values (0.1 ng/mg) revealing sensitivities of 94% and 99%, respectively. (c) 2011 Elsevier Ireland Ltd. All rights reserved.