A cut-off value of 300 ng/mL is used to determine whether cocaine and its metabolites are "screen positive". If screening test is reported as "screen positive", confirmation and identification can be made (at additional charge) by a reference lab using gas chromatography - mass spectrometry. Please submit an add-on order within 7 days of collection if confirmatory testing is needed.
Cocaine is rapidly metabolized in the human body to benzoylecgonine, which this method will detect. The half-life of benzoylecgonine is relatively long, on the order of 6 hours, and the metabolite may appear in the urine for days. Thus, the presence of benzoylecgonine is solid proof of past use, but the timing of the past use cannot be inferred from the urinalysis alone. (Karch, SB., Karch's Pathology of Drug Abuse, Third Edition, 2002; pg.65)