Wolf R. Külpmann
Drug screening: Actual status, pitfalls and suggestions for improvement/Drogenscreening: Gegenwärtiger Stand, Fehlermöglichkeiten und Verbesserungsvorschläge
Immunoassays for drug screening are often regarded as procedures which are easily performed and interpreted. But in fact, many aspects have to be considered to obtain a meaningful result. Among these are sampling, specificity and sensitivity of assays, and quality assessment. Although the mechanised procedures yield quantitative results, there are good reasons to generally report qualitative findings. The mechanised procedures allow the adjustment of the cut-off concentration to the clinical setting, e.g. in the case of acute intoxication, chronic abuse or drug withdrawal, an important advantage as compared to test strips. Procedures for the detection of amphetamines, barbiturates, benzodiazepines or opiates are hampered by the fact that the analytical signal is in principle not related to the pharmacological effect of the contributing drug. A proposal for adjusting the analytical response to the pharmacodynamic action of a compound is presented, as well as a list of drugs for which immunoassays are required. This may give guidance to manufacturers for improving and developing assays. Procedures for individual compounds should in general specifically detect the pertinent metabolite in urine as a proof of drug uptake. Hydrolysis is mandatory in case of poor cross-reactivity of the antibody with the excreted conjugates.
LaboratoriumsMedizin, Walter de Gruyter
Print ISSN: 0025-8466
Volume: 28, 08/2004
Pages: 317 - 325
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