title: The testing of urine specimens for drugs of abuse: background information.
mesh_terms: D002845:Chromatography / Q000379:methods; D019411:Clinical Laboratory Techniques / Q000592:standards*; D005189:False Positive Reactions; D006801:Humans; D008722:Methods; D019966:Substance-Related Disorders / Q000175:diagnosis*; D014481:United States; D014556:Urine / Q000032:analysis*