Journal Article

Comparison of EMIT<sup>®</sup> II, CEDIA<sup>®</sup> and DPC<sup>®</sup> RIA Assays for the Detection of Lysergic Acid Diethylamide in Forensic Urine Samples*

Russell F. Wiegand, Kevin L. Klette, Peter R. Stout and Jay M. Gehlhausen

in Journal of Analytical Toxicology

Volume 26, issue 7, pages 519-523
Published in print October 2002 | ISSN: 0146-4760
Published online October 2002 | e-ISSN: 1945-2403 | DOI:
Comparison of EMIT® II, CEDIA® and DPC® RIA Assays for the Detection of Lysergic Acid Diethylamide in Forensic Urine Samples*

More Like This

Show all results sharing these subjects:

  • Medical Toxicology
  • Toxicology (Non-medical)


Show Summary Details


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 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 (r2 = 0.9062). The specificity of the three assays was assessed using compounds that have structural and chemical properties similar to LSD, common over-the-counter products, prescription drugs and some of their metabolites, and other drugs of abuse. Of the 144 compounds studied, 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 spectrometry 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.

Journal Article.  0 words. 

Subjects: Medical Toxicology ; Toxicology (Non-medical)

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.