Application of the novel immunoassay TRIAGE to a rapid detection of antemortem drug abuse.

The applicability of the immunoassay TRIAGE (E. Merck, Darmstadt, Germany) as a simple and rapid assay for antemortem drug abuse was tested on 100 urine samples from forensic autopsies. The samples were also analyzed by fluorescence polarization immunoassay and by chromatographic methods. The confirmation rate of the TRIAGE results by chromatographic analysis was 92% for benzodiazepines, 95% for cannabinoids, 96% for cocaine, 100% for opiates and barbiturates, and 82% for amphetamines. Because the urine samples were taken from corpses, the latter finding can be explained by false-positive amphetamine results due to cross-reactivity of the antibodies used in current immunoassay technologies with phenylalkylamines, which are generated in postmortem decomposition processes. In fact, tyramine, a typical product of putrefaction, was identified by gas chromatography-mass spectrometry in 11 samples of false-positive amphetamine determinations. TRIAGE produces positive amphetamine results for samples containing tyramine in concentrations of more than 5 mg/L. The detection limit of the TRIAGE assay for 7-aminoflunitrazepam, the major urinary metabolite of flunitrazepam, is within the range of 0.5-1 mg/L.