Immunoassay in healthcare testing applications.

Immunoassay is used extensively for drug testing in pain management. Drug testing for the purpose of compliance monitoring is fundamentally different from forensic applications, which may rely on immunoassay screening to rapidly identify "negative" samples. In clinical settings, focus is shifted from identification of select drugs of abuse with low positivity rates to detection of a wide variety of licit and illicit compounds with expected high positivity rates. The primary drug classes of interest in this population, opioids and benzodiazepines, require special testing considerations when immunoassay is used. This review highlights the performance characteristics of immunoassay, with special emphasis on prescription drug classes and testing at the point-of-care.

Prevalence of synthetic cannabinoids in U.S. athletes: initial findings.

A number of synthetic cannabinoids such as JWH-018 and JWH-073 have been incorporated into "spice" products. Despite having labels warning against human consumption, the products are smoked for their cannabinoid-like effects and the extent of their use by athletes has not been adequately described. Urine samples collected from 5,956 athletes were analyzed by high-performance liquid chromatography-tandem mass spectrometry for the presence of JWH-018, JWH-073, and their metabolites. Metabolites of JWH-018 and/or JWH-073 were detected in 4.5% of the samples. Metabolites of JWH-018 and JWH-073, only JWH-018, and only JWH-073 were detected in 50%, 49%, and approximately 1% of positive samples, respectively. In total, JWH-018 metabolites were detected in 99% (50% + 49%) and JWH-073 metabolites were detected in approximately 50% (49% + 1%) of the positive samples. Parent JWH-018, JWH-018-2-OH-indole, and JWH-018-4-OH-indole were not detected in any of the samples. All samples in which JWH-073 metabolites were detected contained JWH-073-N-butanoic acid. Parent JWH-073 and its N-(4-OH-butyl), 4-OH-indole, 5-OH-indole, and 7-OH-indole metabolites were not detected. Given the number of synthetic cannabinoids that have been synthesized, their limited regulation, and the prevalence of JWH-018 and JWH-073 metabolites detected in the athletes, these compounds should remain a priority for anti-doping programs.

Screening indicators of dehydroepiandosterone, androstenedione, and dihydrotestosterone use: a literature review.

Because of their perceived and reported effects on self-image, muscle development, performance, and similar factors, anabolic-androgenic steroids (AAS) and their precursors are among the most abused substances by professional, amateur, and recreational athletes. However, AAS abuse is not limited to athletes, but is also prevalent in the workplace, especially those professions in which image, strength, and endurance are coveted attributes. The detection of many steroids in biological specimens is analogous to the detection of an abused drug such as cocaine. Identification of the parent drug or its characteristic metabolite(s) in a donor's sample with a drug screening technique and confirmation of the drug/metabolite with a suitable alternative technology provides evidence of use. These analyses and subsequent interpretive scenarios become far more complex when the ingested AAS is an endogenous compound such as dehydroepiandrosterone (DHEA), androstenedione (Adione), or dihydrotestosterone (DHT). These compounds and their metabolites are present in specimens such as urine as a course of our natural endocrine function. Therefore, it becomes much more challenging for the laboratory to establish testing and interpretative paradigms that can distinguish "normal" urinary profiles of these steroids and their metabolites from profiles indicative of exogenous use. Distinguishing "normal" from "abnormal" urine profiles is particularly challenging during screening when literally tens of steroids and their metabolites may be tested simultaneously in a single chromatographic analysis. The purpose of this paper is to review the relevant literature about DHEA, Adione, and DHT administration, detection, and interpretation specifically as it relates to changes in the urinary AAS profile that may be identified during the routine laboratory screening of donor urine specimens.

Analysis of nitrite in adulterated urine samples by capillary electrophoresis.

A simple method for analyzing nitrite in urine has been developed to confirm and quantify the amount of nitrite in potentially adulterated urine samples. The method involved separation of nitrite by capillary electrophoresis and direct UV detection at 214 nm. Separation was performed using a bare fused silica capillary and a 25 mM phosphate run buffer at a pH of 7.5. Sample preparation consisted of diluting the urine samples 1:20 with run buffer and internal standard, and centrifuging for 5 min at 2500 rpm. The sample was hydrodynamically injected, then separated using -25 kV with the column maintained at 35 degrees C. The method had upper and lower limits of linearity of 1500 and 80 microg/mL nitrite, respectively, and a limit of detection of 20 microg/mL. The method was evaluated using the National Committee for Clinical Laboratory Standards (NCCLS) protocol (Document EP10-A2), and validated using controls, standards, and authentic urine samples. Ten anions, ClO-, CrO4(-2), NO3-, HCO3-, I-, CH3COO-, F-, SO4-, S2O8(-2), and Cl-, were tested for potential interference with the assay. Interferences with quantitation were noted for only CrO4(-2) and S2O8(-2). High concentrations of Cl- interfered with the chromatography. The method had acceptable accuracy, precision, and specificity.

Determination of chromate adulteration of human urine by automated colorimetric and capillary ion electrophoretic analyses.

Various chemicals can be added to urine specimens collected for drug analysis to abnormally elevate ionic concentrations and/or interfere with either immunoassay urine drug-screening procedures or gas chromatographic-mass spectrometric confirmation techniques. One such adulterant, "Urine Luck" (formula 5.3), has been identified in our previous research to contain potassium dichromate. Screening of suspected adulterated specimens and confirmation of the adulterant are important for forensic drug screening. The application and comparison of automated colorimetric and capillary ion electrophoretic techniques for the detection, confirmation, and quantitation of chromate adulteration of urine specimens were the purpose of this investigation. Thirty-six urine specimens suspected of adulteration were analyzed for chromate by colorimetric analysis with diphenylcarbazide. Duplicate aliquots were analyzed for chromate by capillary ion electrophoresis. Results of the colorimetric chromate analyses revealed a mean chromate concentration of 929 microg/mL with a standard error of 177 microg/mL and a range of 30 to 5634 microg/mL. Results of the capillary ion electrophoresis chromate analyses revealed a mean chromate concentration of 1009 microg/mL with a standard error of 218 microg/mL and a range of 20 to 7501 microg/mL. The correlation coefficient between the capillary ion electrophoretic and colorimetric chromate results was r = 0.9669. Application of the automated diphenylcarbazide colorimetric technique provides rapid determination of chromate adulteration of a urine specimen. Capillary ion electrophoresis offers a separation technique to confirm the presence of chromate in suspected adulterated specimens. The excellent correlation between these methods substantiates their application to forensic testing as screening and/or confirmation techniques.