This assay provides only a preliminary analytical test result. A more specific alternate chemical method must be used in order to obtain a confirmed analytical result. Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method. The test does not distinguish between drugs of abuse and certain medications. A positive result may be obtained from certain foods or food supplements. Clinical consideration and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used.