The National Forensic Science Technology Center evaluated three types of Narcotic Screening Tests manufactured by M.M.C. International B.V., with each test designed to presumptively identify specific target drugs: crack/cocaine, methamphetamine and MDMA, and heroin.
The evaluation found that the limit of detection closely matched the value found in the product insert of less than 0.3 mg. The kits were reproducibly sensitive to crack/cocaine (approximately 0.5 mg for cocaine HCl and cocaine base); heroin (approximately 0.1 mg); and crystal meth/XTC (approximately 0.1 mg for both methamphetamine and MDMA). The three kits correctly identified their compounds of interest, with sensitivity in mixtures reproducible at reported ratios (target compound to diluent). Given the presumptive nature of colormetric tests, the kits performed with acceptable specificity, with reported "false" positives observed in at least one trial from the sample set. The tests were rugged, producing positive results with the target drugs after 2 weeks of exposure to hot/dry, hot/humid, cold, and freezing storage conditions. The tests contain a reagent-granulate that is advertised not to require neutralization. The tests' small volumes make them safer than conventional colorimetric tests. Limitations pertain to the nature of colorimetric testing. It is presumptive and cannot identify a substance to the exclusion of all others. In addition, colorimetric testing is appropriate for solid or liquid samples only and should not be used on paraphernalia. In addition, the color often continued to change throughout the testing time frame, giving an immediate color and darkening over time or changing color; multiple colors were present in a number of tests. Areas for improvement, training requirements, and health and safety issues are discussed. The evaluation included assessment of conformity, reproducibility, limit of detection, specificity, mixture sensitivity, and ruggedness. The tests were performed in duplicate by independent evaluators. Appended tabular data