A new automated assay for the detection of synthetic urine in drug testing

Abstract

Urine drug testing can be subject to attempts to dilute, adulterate, or substitute the specimen. Substitution may involve the use of commercially available synthetic urine. Current laboratory methods to detect specimen validity often fail to detect these products. We evaluated a new automated assay designed to detect synthetic urine. We determined that the assay met performance requirements and accurately identified five commercially obtained products as synthetic urine while not identifying known normal urine as synthetic. However, in a group of 843 patient urine samples, 40 of the 46 urine samples identified as “synthetic” were samples with creatinine <50 mg/dL. Fourteen of the 40 were actually positive for drugs of abuse. We conclude that the test is analytically valid but clinically limited. We recommend that it be used in conjunction with other indicators of synthetic urine. We suggest a scheme that would achieve this, and reporting terminology that would reflect the limits of the analysis.

Advances in testing for sample manipulation in clinical and forensic toxicology - Part A: urine samples

“…Similar percentages as in the former study of random urine samples (5.4%, total of 843 urine specimens) were determined as potentially substituted (fake) urine. Most indicated low creatinine values, though, which would allow the assumption that in some cases, the unknown target analyte of the assay could be diluted to such an extent that it would (falsely) indicate synthetic urine [ 33 ]. However, without knowledge of the test principle or target analyte, reliability assessment of the test, also with potentially changing synthetic urine products entering the market, remains problematic.…”

Identificación de adulteración de muestras de orina en el análisis toxicológico

“…Debido a la poca invasividad en la recolección, la disponibilidad en cantidades adecuadas y la facilidad del análisis, la orina ha sido la matriz de elección para la detección de sustancias de abuso durante muchos años por encima de otras alternativas como el sudor o la saliva (Silva et al, 2019). Sin embargo, uno de los retos actuales para los laboratorios es la facilidad con la que pueden ser manipuladas las muestras de orina con el propósito de producir falsos negativos que permitan evadir las consecuencias del empleo de diferentes sustancias, por ejemplo, las sustancias de abuso o los fármacos que dan ventajas a los atletas en los eventos deportivos.…”