Clinical Chemistry Link to Randox Laboratories Web Site
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 42: 34-38, 1996;
This Article
Right arrow Full Text (PDF)
Right arrow Submit an electronic Letter to
the Editor about this paper
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Spiehler, V.
Right arrow Articles by Niedbala, R. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Spiehler, V.
Right arrow Articles by Niedbala, R. S.

Clinical Chemistry, Vol 42, 34-38, Copyright © 1996 by American Association for Clinical Chemistry

Enzyme immunoassay validation for qualitative detection of cocaine in sweat

V Spiehler, J Fay, R Fogerson, D Schoendorfer and RS Niedbala
Spiehler and Associates, Newport Beach, CA 92663, USA. spiehleraa@aol.com

A solid-phase enzyme immunoassay (EIA) involving microtiter plates was modified for analysis of cocaine in sweat. Sweat was collected with the PharmChek sweat patch and drugs were eluted from the collection pad of the patch. The sweat contained primarily parent cocaine. The assay was determined to have cross-reactivity for cocaine of 102% relative to 100% for the benzoylecgonine (BE) calibrators and for cocaethylene of 148%. The optimum cutoff concentration for this modified assay, determined by receiver-operating characteristic curve analysis, was 10 micrograms/L cocaine or BE equivalents. At this concentration the assay had 94.5% sensitivity and 99.1% specificity vs gas chromatography-mass spectrometry (GC-MS) as an acceptable indicator of the true clinical state. The positive predictive value at a prevalence of 50% was 99%. Threshold analysis for positives suggested that the 95% confidence interval for a positive result by the EIA was between 12.5 and 15 micrograms/L and that quality-control samples at 5 and 15 micrograms/L could be run with each batch to certify the precision around the cutoff. All positive samples must be confirmed by GC-MS. The sensitivity and specificity of the overall analysis system (immunoassay screen and GC-MS confirmation) was 86% and 97%, with known cocaine dosing of volunteers as the acceptable indicator of the true clinical state.


The following articles in journals at HighWire Press have cited this article:


Home page
 Clin. Chem.Home page
M. Sarno, H. Powell, G. Tjersland, D. Schoendorfer, H. Harris, K. Adams, P. Ogata, and G. R. Warnick
A Collection Method and High-Sensitivity Enzyme Immunoassay for Sweat Pyridinoline and Deoxypyridinoline Cross-Links
Clin. Chem., September 1, 1999; 45(9): 1501 - 1509.
[Abstract] [Full Text] [PDF]

Home page
 Clin. Chem.Home page
P. Kintz, R. Brenneisen, P. Bundeli, and P. Mangin
Sweat testing for heroin and metabolites in a heroin maintenance program
Clin. Chem., May 1, 1997; 43(5): 736 - 739.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1996 by the American Association for Clinical Chemistry.