Asian Journal of Chemical Sciences

Abuse of methamphetamine is one of the major social problem faced by many countries. Oral fluid as an alternative matrix for assessing drugs of abuse is gaining prominence. It is therefore essential to investigate assay performance and limitations of screening techniques for methamphetamine in oral fluid. The purpose of this study was to evaluate the validity of Alere^TM methamphetamine microplate competitive enzyme-linked immunosorbent assay (ELISA) for the analysis of methamphetamine in oral fluid. Ten samples were analysed in the laboratory using the Alere^TM Methamphetamine ELISA kit, and the results were compared to the results obtained using gas chromatography-mass spectrometry(GC-MS) with good precisions (intra = 2.88%, inter = 9.04%) and accuracy (R² =0.9975). True negative, true positive, false negative and false positive results were determined by the GC-MS analysis. The result of the samples consisted 6 true negatives, 3 true positives and 1 false negative within the cut off concentration of 100 ng/mL. The results also demonstrated a functional sensitivity and specificity of 75% and 100% respectively. All the tested cross-reactive drugs showed cross-reactivity of less than 10% with methamphetamine except for MDMA which showed cross-reactivity of 44%. These data show that Alere^TM methamphetamine microplate ELISA is a fast, precise and accurate screening technique for the detection of methamphetamine in oral fluid samples.