In order to determine how designer drugs may or may not react in presumptive screens with pre-existing commercial immunoassays, this project determined the cross-reactivity of 30 designer drugs with 16 ELIISA reagents from four different companies; and two EMIT reagents were evaluated in order to determine the cross-reactivity of these same compounds in urine.
Cross-reactivity toward most of the tested drugs was greater than 4 percent in assays that targeted amphetamine or methamphetamine. Compounds such as MDA, MDMA, ethylamphetamine, and alpha-methyltryptamine demonstrated cross-reactivities in the range of 30-250 percent, but data were consistent with both manufacturers' inserts and published literature. Some assays - such as BZP, cotinine, PCP, mephentermine, methylphenidate, ketamine, and MDPV - demonstrated almost no cross-reactivity toward any of the analytes evaluated. When tested against the Randox Mephedrone/Methcathinone kit, cathinone derivatives showed cross-reactivity at concentrations as low as 150 ng/ml. The Mephedrone/Methcathinone kit was not a suitable assay for detecting other more traditional amphetamine-derived compounds, but may be more appropriate for screening post-mortem specimens for "bath salts" when putrefactive amines may be present. All other assays demonstrated essentially no cross-reactivity toward any of the analytes assessed. Given these results, there is clearly a need for additional broad-range screening techniques that can be applied when analyzing biological specimens for drugs of abuse, specifically the more recent designer drugs. 16 tables, 4 figures, a 42-item bibliography, and information on research dissemination