Analytical methodology.
D002845:Chromatography / Q000379:methods; D019411:Clinical Laboratory Techniques / Q000379:methods*; D006801:Humans; D013287:Illicit Drugs / Q000032:analysis*; D007118:Immunoassay / Q000379:methods; D012680:Sensitivity and Specificity; D019966:Substance-Related Disorders / Q000175:diagnosis*; D014556:Urine / Q000032:analysis*
D013287:Illicit Drugs