Drug abuse proficiency testing.

Concerning drugs in general, proficiency testing has undoubtedly been a major contributing factor to improved detection. Some of the improvement may be due to advances in technology, and this is possibly the case with improvement in the detection of morphine and methadone. The improvement in the determination of methamphetamine within three surveys over six months can clearly be attributed to proficiency testing. In drug screening for cocaine abuse, the poor results in proficiency testing for the detection of the primary metabolite, benzoylecgonine, has clearly demonstrated that laboratories are not proficient in this screening.