Peroxidase Activities in Urine Adulteration

Stealth is an adulterant advertised as an effective way to beat a urine drug test. Stealth consists of two vials, one containing a powder (peroxidase) and a second one containing a liquid (peroxide). Combining the contents of both vials results in a strong oxidizing potential capable of oxidizing several drugs and metabolites. Stealth can mask detection of marijuana metabolite, LSD, and opiate (morphine) at 125-150% of cut-off values assayed by Roche OnLine and Microgenic's CEDIA® immunoassay (16). Low concentration of morphine (2500 ng/mL) could be effectively masked by Stealth, but not higher concentrations (6000 ng/mL). Stealth also affects the GC-MS confirmation step. Cody et al. (17) reported that results of GC-MS analysis of Stealth-adulterated urine using standard procedures proved unsuccessful in several cases, and in 4 out of 12 cases, neither the drug nor the internal standard was recovered. Addition of sodium disulfite prior to extraction allowed recovery of both drugs and internal standard. However, concentrations of morphine and codeine were reduced by 17 to 30%.

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