These authors contributed equally and should be considered co-first authors.
Agreement of anti-neutrophil cytoplasmic antibody measurements obtained from serum and plasma
Article first published online: 16 AUG 2006
Clinical & Experimental Immunology
Volume 146, Issue 1, pages 15–20, October 2006
How to Cite
Lee, A. S., Finkielman, J. D., Peikert, T., Hummel, A. M., Viss, M. A., Jacob, G. L., Homburger, H. A., Specks, U. and for the Wegener's Granulomatosis Etanercept Trial Research Group (2006), Agreement of anti-neutrophil cytoplasmic antibody measurements obtained from serum and plasma. Clinical & Experimental Immunology, 146: 15–20. doi: 10.1111/j.1365-2249.2006.03179.x
- Issue published online: 25 AUG 2006
- Article first published online: 16 AUG 2006
- Accepted for publication 11 July 2006
- anti-neutrophil cytoplasmic;
- enzyme-linked immunosorbent assay;
- fluorescent antibody technique;
Serum and plasma are used interchangeably to measure anti-neutrophil cytoplasmic antibodies (ANCA), even though the release of ANCA target antigens during the preparation of serum could affect ANCA assays and cause discrepancies between the results obtained from serum and plasma. To what extent ANCA test results obtained from serum agree and correlate with results from plasma remains unknown. Therefore, a comprehensive comparison was performed using serum and plasma samples which were collected in 175 patients with active Wegener's granulomatosis at enrolment of a recent randomized trial. These paired serum and plasma samples were subjected to parallel ANCA testing by standard indirect immunofluoresence on ethanol-fixed neutrophils, a direct enzyme-linked immunoassay (ELISA) for proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, and two different capture ELISAs for PR3-ANCA. The concordance of categorical serum and plasma ANCA results was assessed using κ-coefficients. These were > 0·8 for all assays, indicating a very good concordance between positive and negative serum and plasma results. Spearman's correlation coefficients for serum and plasma PR3-ANCA values obtained by direct ELISA and both capture ELISAs were ≥ 0·95 (P < 0·0001). Our study shows that serum and plasma samples can be used interchangeably for measuring ANCA.