Lack of specificity of cyclosporine immunoassays. Results of a College of American Pathologists Study.


Journal Article

OBJECTIVE: To evaluate the cross-reactivity of the 6 most abundant cyclosporine A (CsA) metabolites in commonly used assays for CsA. DESIGN: Whole blood samples containing either only 62 ng/mL CsA (A) or 62 ng/mL CsA and between 49 and 86 ng/mL of 1 of the 6 most abundant CsA metabolites (B) were lyophilized. One sample of A and 1 of B were mailed to each of the laboratories participating in the College of American Pathologists Proficiency Testing Program quarterly during a 3-year period (1999-2001). Method means and coefficients of variation were calculated for each mailing. RESULTS: The study showed significant cross-reactivity of metabolites in all the immunoassay systems studied. Overall degree of interference decreased from Abbott TDx polyclonal > Abbott TDx monoclonal > DiaSorin > Syva EMIT. High-performance liquid chromatography methods gave results close to those found using mass spectrometric techniques. CONCLUSIONS: Significant metabolite interference was found to occur with the immunoassay systems studied.

Full Text

Duke Authors

Cited Authors

  • Soldin, SJ; Steele, BW; Witte, DL; Wang, E; Elin, RJ; College of American Pathologists Study,

Published Date

  • January 2003

Published In

Volume / Issue

  • 127 / 1

Start / End Page

  • 19 - 22

PubMed ID

  • 12521361

Pubmed Central ID

  • 12521361

Electronic International Standard Serial Number (EISSN)

  • 1543-2165

Digital Object Identifier (DOI)

  • 10.1043/0003-9985(2003)127<19:LOSOC>2.0.CO;2


  • eng

Conference Location

  • United States