Systematic investigations of novel validity parameters in urine drug testing and prevalence of urine adulteration in a two‐year cohort

Abstract

Urinalysis is well established for drug screening. Various methods of urine adulteration such as dilution, addition of oxidative/reductive chemicals or detergents, and handing over urine-like fluids are used to circumvent a positive screen. Validity parameters such as determination of pH, gravidity, urine temperature, or testing for oxidative/reductive chemicals are therefore used to uncover adulterated urine specimens. However, synthetic urine ("fake urine") has nowadays been used for manipulations, leading to inconspicuous results with common validity test systems. Therefore, the aims of the study were (a) to evaluate additional validity parameters, (b) to evaluate the prevalence of urine adulteration, (c) to identify adulteration markers in purchased fake urine samples. Urine samples (n = 550) submitted for drug abstinence testing were analyzed by a standard urine liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening approach using library-assisted identification of 10 different endogenous biomolecules. The detection rates of biomolecules in authentic samples were phenylalanine (93.4%), tryptophan (97.1%), propionyl-carnitine (67.1%), butyryl-carnitine (99.6%), isovaleryl-carnitine (92.8%), hexanoyl-carnitine (91.0%), heptanoyl-carnitine (97.1%), octanoyl-carnitine (98.9%), and indoleacetylglutamine (98,2%). Phenylacetylglutamine was detected in each authentic sample. Based on the detection rates and measured creatinine levels, six manipulated samples were identified in this study. In two cases, fake urine was handed over, one time fake urine was most likely used for dilution. Once dilution with other fluids was used as adulteration method, while in another sample a detergent solution was handed over. Additionaly, one sample contained reactive chemicals. All fake urine samples were additionally identified by the detection of unique polyglycole patterns, which were observed in purchased fake urine samples.

Pitfalls in drug testing by hyphenated low‐ and high‐resolution mass spectrometry

“…Another example is an acute paracetamol poisoning. 12 Steuer et al [13][14][15][16] described interesting metabolomic strategies for detection of sample manipulations using liquid chromatography-high resolution mass spectrometry (LC-HRMS). 4 Pitfalls concerning TDM in dried blood spots (DBS) are reviewed by Antunes et al 5 with special focus on influence of the hematocrit on the plasma concentrations.…”

“…9-11 recently systematic investigations of novel validity parameters in urine drug testing and prevalence of urine adulteration. 12 Steuer et al [13][14][15][16] described interesting metabolomic strategies for detection of sample manipulations using liquid chromatography-high resolution mass spectrometry (LC-HRMS). In their recent review article, 13 they discussed different applications of metabolomic strategies in biomarker research for indirect identification of drug consumption and sample manipulation.…”

Evaluation of endogenous urinary biomarkers for indirect detection of urine adulteration attempts by five different chemical adulterants in mass spectrometry methods

“…6 Urine tampering methods range from urine substitution through artificial urine to dilution or chemical adulteration. 4,9,10 With recent intentions in several US states to ban artificial urine products, chemical adulteration attempts might become of higher interest. Integrity testing, spot and dipstick tests, or integrated sample checks to commercially available immunoassay systems are often performed as a time-and cost-effective alternative but are associated with high rates of false positives or false negatives 3,7,8 Today, the extent of urine tampering remains largely unknown.…”

“…Integrity testing, spot and dipstick tests, or integrated sample checks to commercially available immunoassay systems are often performed as a time-and cost-effective alternative but are associated with high rates of false positives or false negatives 3,7,8 Today, the extent of urine tampering remains largely unknown. 9 Similarly, monitoring of degraded and/or oxidized endogenous urinary compounds as indirect markers of chemical adulteration attempts was exemplified for the adulterant potassium nitrite (KNO 2 ). 4,9,10 With recent intentions in several US states to ban artificial urine products, chemical adulteration attempts might become of higher interest.…”

Suitability evaluation of new endogenous biomarkers for the identification of nitrite‐based urine adulteration in mass spectrometry methods

“…11 Systematic studies on the prevalence of adulteration attempts are scarce and it can be assumed that such attempts are detected only in rare cases. 1,12 With recent intentions in several US states to ban artificial urine products, chemical adulteration attempts might become of higher interest. 13 On a mechanistic basis, adulterants may interfere with components of the immunoassay principle or degrade drugs or their metabolites through oxidation unreliable for any analytical detection.…”