Retrospective analysis of some L-methamphetamine/L-amphetamine urine data.

A limited analysis is presented of data accumulated over about three years for specimens containing either nonracemic L-methamphetamine/L-amphetamine or racemic mixtures of the D and L stereoisomers. 55 data points for both nonracemic L-methamphetamine and racemic mixtures show that it is possible to report a specimen containing L-methamphetamine positive for illegal D-methamphetamine based on current guidelines unless chiral assays are performed on selected methamphetamine positives. Generation of only 45 racemic specimens from chiral analysis of about 5,000 urine methamphetamine positives demonstrates the overwhelming prevalence of nonracemic illegal D-methamphetamine in Southern California.