Nitrite Adulteration of Workplace Urine Drug-Testing Specimens I. Sources and Associated Concentrations of Nitrite in Urine and Distinction Between Natural Sources and Adulteration

Abstract

The active ingredient in the commercial workplace urine drug-testing adulterant, Klear, was previously determined to be nitrite ion. Nitrite adulteration compromises the confirmation of some drugs, notably the marijuana metabolite. A previously reported bisulfite step overcomes some nitrite adulteration, but it cannot do so in every case, which leaves the laboratory to report the specimen as not suitable for testing. Unlike many other adulterants, nitrite is found in normal urine at low concentrations. In order to defend a report of nitrite adulteration, it is necessary to provide evidence that the amount of nitrite in a workplace urine specimen could not arise by normal means. The objectives of this study were to identify all sources of nitrite in urine and the range of concentrations associated with these sources and to determine if nitrite adulteration can be supported based upon a quantitative result. The scientific literature was reviewed for internal and external sources of nitrite and their concentration ranges and are reported. The following specimens were obtained and nitrite concentrations measured by a spectrophotometric method: clinical specimens nitrite positive by test strip (< 15 micrograms/mL); specimens culture positive for nitrate-reducing microorganisms (< 36 micrograms/mL); specimens from patients on medications that may metabolize to nitrite (< 6 micrograms/mL); and drug-test specimens, both negative (< 130 micrograms/mL) and others that appeared to be adulterated with nitrite (range 1910-12,200 micrograms/mL, mean 5910). The literature and the nitrite measurements of this study indicate a substantial difference between concentrations from natural sources compared with adulteration. A quantitative measurement of nitrite by a well-structured assay can provide scientifically valid and forensically defensible proof of adulteration with a nitrite-containing substance.

Detection and identification of 2‐nitro‐morphine and 2‐nitro‐morphine‐6‐glucuronide in nitrite adulterated urine specimens containing morphine and its glucuronides

“…The KNO 2 concentrations of 0.05 M and 0.6 M were selected based on the concentrations detected in nitrite adulterated urine specimens (0.04-0.3 M or 1910-12200 mg/ml [15] ). Solid KNO 2 was considered as the preferred form due to its easy application during adulteration process.…”

2-Nitro-6-monoacetylmorphine: potential marker for monitoring the presence of 6-monoacetylmorphine in urine adulterated with potassium nitrite

“…An objective of the study was to determine the effect of nitrite on the CEDIA® 6-AM assay. Two nitrite concentrations at 0.05 and 0.6 M were chosen following consideration of its concentration range (0.04-0.3 M or 1,910-12,200 μg/mL) reported in adulterated urine specimens [15].…”

“…Nitrite at 0.05 M would also be suitable for this experiment, as both nitrite concentrations appeared to exhibit the same effects on the CEDIA assay. However, 0.6 M nitrite was chosen after considering the fact that many adulterated urine specimens were found to contain higher nitrate concentrations (higher than 0.05 M) [15].…”

Dosage des amphétamines dans les cheveux, la salive et les urines

“…The main advantage of oral fluid over urine for workplace testing is that the collection of the specimen is observed, cir¬ cumventing the additional expense of testing for adulte¬ rants in the laboratory (9,10). There are several review papers regarding the analysis of drugs in oral fluid (11), and there are a number of published articles specific to the disposition of methamphetamine in plasma and sali¬ va following administration (12,13 …”

“…metropolitan areas, reported that methamphetamine-related episodes increased by 30% from approximately 10,400 in 1999 to 13,500 in 2000, although there had previously been a significant decrease in methamphetamine-related episodes repor¬ ted between 1997 (17,200) and 1998 (11,500).…”