Method Description

Adulterant:

All results are measured using spectrophotometry at wavelengths specified by the reagent manufacturer. The use of a refractometer may also be used in the specific gravity measurement.(Package inserts: Specimen Validity Test Creatinine. Roche Diagnostics; V3.0, 08/2015; Specimen Validity Test Nitrite. Roche Diagnostics; V3.0, 08/2018, Specimen Validity Test Oxidant. Roche Diagnostics; V 3.0, 08/2018; Specimen Validity Test pH Roche Diagnostics; V3.0, 02/2019, Specimen Validity Test Specific Gravity. Roche Diagnostics; V4.0, 08/2022)

Drug Panel:

The barbiturate, cocaine metabolite, and tetrahydrocannabinol metabolite assays are based on the kinetic interaction of microparticles in a solution as measured by changes in light transmission. In the absence of sample drug, soluble drug conjugates bind to antibody-bound microparticles, causing the formation of particle aggregates. As the aggregation reaction proceeds in the absence of sample drug, the absorbance increases. When a urine sample contains the drug in question, this drug competes with the drug derivative conjugate for microparticle-bound antibody. Antibody bound to sample drug is no longer available to promote particle aggregation, and subsequent particle lattice formation is inhibited. The presence of sample drug diminishes the increasing absorbance in proportion to the concentration of drug in the sample. Sample drug content is determined relative to the value obtained for a known cutoff concentration of drug.(Package inserts: BARB. Roche Diagnostics; V 13.0, 09/2021; THC2. Roche Diagnostics; V 13.0, 03/2022; COC2. Roche Diagnostics; V 9.0, 03/2019)

Targeted Screening Panels for opioids, benzodiazepines, and stimulants:

The urine sample is diluted with internal standard and clinical laboratory reagent water and then analyzed by liquid chromatography tandem mass spectrometry using a high resolution-accurate mass orbitrap detector.(Unpublished Mayo method)

Ethyl Glucuronide Screen:

This assay is a homogeneous, semiquantitative enzyme immunoassay. The assay is based on competition between free drug in the urine sample and a drug labeled with the enzyme glucose-6-phosphate dehydrogenase for a fixed amount of specific antibody binding sites. Active enzyme converts nicotinamide adenine dinucleotide (NAD[+]) to NADH, which results in an absorbance change that can be measured spectrophotometrically at 340 nm.(Package insert: DRI Ethyl Glucuronide Assay. Microgenics Corporation; 09/2015)

Nicotine and Metabolites:

Nicotine and metabolites are extracted from urine by solid-phase extraction techniques. The extract eluate is quantified by high-performance liquid chromatography tandem mass spectrometry.(Moyer TP, Charlson JR, Enger RJ, et al. Simultaneous analysis of nicotine, nicotine metabolites, and tobacco alkaloids in serum or urine by tandem mass spectrometry, with clinically relevant metabolic profiles. Clin Chem. 2002;48[9]:1460-1471; Oh J, Park MS, Chun MR, et al. A simple and high-throughput LC-MS/MS method for simultaneous measurement of nicotine, cotinine, 3-OH cotinine, nornicotine, and anabasine in urine and its application in the general Korean population. J Anal Toxicol. 2022:46(1):25-36. doi:10.1093/jat/bkaa177)