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False-positive interferences of common urine drug screen immunoassays: a review
- J Anal Toxicol
"... Urine drug screen (UDS) immunoassays are a quick and inexpensive method for determining the presence of drugs of abuse. Many cross-reactivities exist with other analytes, potentially causing a false-positive result in an initial drug screen. Knowledge of these potential interferents is important in ..."
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Urine drug screen (UDS) immunoassays are a quick and inexpensive method for determining the presence of drugs of abuse. Many cross-reactivities exist with other analytes, potentially causing a false-positive result in an initial drug screen. Knowledge of these potential interferents is important in determining a course of action for patient care. We present an inclusive review of analytes causing false-positive interferences with drugs-of-abuse UDS immunoassays, which covers the literature from the year 2000 to present. English lan-guage articles were searched via the SciFinder platform with the strings ‘false positive [drug] urine ’ yielding 173 articles. These arti-cles were then carefully analyzed and condensed to 62 that included data on causes of false-positive results. The discussion is separated into six sections by drug class with a corresponding table of cross-reacting compounds for quick reference. False-positive results were described for amphetamines, opiates, benzodiazepines, cannabi-noids, tricyclic antidepressants, phencyclidine, lysergic acid diethyl-amide and barbiturates. These false-positive results support the generally accepted practice that immunoassay positive results are considered presumptive until confirmed by a second independent chemical technique.
Review and Recommendations for Drug Testing in Substance Use Treatment Contexts Special Annual Review Article Open Access
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Assays for the Detection of Lysergic Acid Diethylamide in Forensic Urine Samples*
"... In an effort to determine a practical, efficient, and economical alternative for the use of a radioimmunoassay (RIA) for the detection of lysergic acid diethylamide (LSD) in human urine, the performance of two photometric immunoassays (Dade Behring EMIT II and Microgenics CEDIA) and the Diagnostics ..."
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In an effort to determine a practical, efficient, and economical alternative for the use of a radioimmunoassay (RIA) for the detection of lysergic acid diethylamide (LSD) in human urine, the performance of two photometric immunoassays (Dade Behring EMIT II and Microgenics CEDIA) and the Diagnostics Products Corp. (DPC) RIA were compared. Precision, accuracy, and linearity of the 3 assays were determined by testing 60 replicates (10 for RIA) at 5 different concentrations below and above the 500.pg/mt LSD cut-off. The CEDIA and RIA exhibited better accuracy and precision than the EMIT II immunoassay. In contrast, the EMIT II and CEDIA demonstrated superior linearity r2 = 0.9809 and 0.9540, respectively, as compared with the RIA (~- = 0.9062). The specificity of the three assays was assessed using compounds that have structural and chemical properties imilar to LSD, common over-the-counter products, prescription drugs and some of their metabolites, and other drugs of abuse. Of the 144 compounds tudied, the EMIT II cross.reacted with twice as many compounds as did the CEDIA and RIA. Specificity was also assessed in 221 forensic human urine specimens that previously screened positive for LSD by the EMIT II assay. Of these, only 11 tested positive by CEDIA, and 3 were positive by RIA. This indicated a comparable specificity performance between CEDIA and RIA. This also was consistent with a previously reported high false-positive rate of EMIT II (low specificity). Each of the immunoassays correctly identified LSD in 23 out of 24 human urine specimens that had previously been found to contain LSD by gas chromatography-mass pectrometry at a cut-off concentration of 200 pg/mL The CEDIA exhibited superior precision, accuracy, and decreased cross-reactivity to compounds other than LSD as compared with the EMIT II assay and does not necessitate the handling of radioactive materials. * Disclaimer: The opinions contained in the publication are not to be construed a official or as
Saskatoon
"... may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work, in their absence, by the Head of the Department or the Dean ..."
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may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis or parts thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis.
