An evaluation of six methods for the detection of drugs of abuse in urine.

The detection of drugs of abuse in urine by four commercial immunoassay systems (TDx, BCL and PFI-20 opiates, and PFI-20 morphine) and one commercial TLC system (Toxi-Lab) was investigated and results compared with those obtained by a dual-column capillary GC system. The TDx system was the most reliable method for preliminary screening of urines for opiates; all the commercial immunoassay systems gave some results which were at variance with those of the GC. The GC method proved to be more reliable than the commercial TLC system in discriminating between the different opiates and is recommended for identification of drugs of abuse in urine specimens in which positive results have been obtained with preliminary screening procedures.