Abstract | OBJECTIVE: DESIGN AND METHODS: Standard protocols were used to verify analytical performance claims. Anti-dsDNA antibody levels in SLE patient specimens (N=105) were measured and assessed for clinical performance using manufacturer cut-off limits along with the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score. RESULTS: Assay precision, measurable range and normal reference interval met the manufacturers' stated claims. Agreement between Farr and BioPlex assays was moderate (positive agreement=62%; negative agreement=85%; kappa=0.48), as was agreement between Farr and Farrzyme assays (positive agreement=56%; negative agreement=91%; kappa=0.51). Mean SLEDAI-2K scores differed significantly between the anti-dsDNA positive and negative groups for BioPlex (p=0.0006), but not Farr (p=0.11) or Farrzyme (p=0.34). ROC curve analysis showed a similar area under the curve (AUC) for all three assays (0.76, 0.74, and 0.73 for Farr, BioPlex, and Farrzyme, respectively) in the discrimination of clinically active disease. Furthermore, increased anti-dsDNA levels from BioPlex showed significant correlation with active renal disease. However, results suggested a lower cut-off for the Farrzyme assay for assessment of global disease activity. CONCLUSIONS:
BioPlex and Farrzyme assays had similar overall agreement with the Farr assay, with BioPlex best reflecting disease activity in SLE patients.
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Authors | Allison A Venner, Dominique Ibañez, Dafna D Gladman, Murray B Urowitz, Anne MacKinnon, Ivan M Blasutig, Paul M Yip |
Journal | Clinical biochemistry
(Clin Biochem)
Vol. 46
Issue 4-5
Pg. 317-20
(Mar 2013)
ISSN: 1873-2933 [Electronic] United States |
PMID | 23246539
(Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved. |
Chemical References |
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Topics |
- Adult
- Aged
- Autoantibodies
(blood)
- DNA
(immunology)
- Enzyme-Linked Immunosorbent Assay
(standards)
- Female
- Humans
- Lupus Erythematosus, Systemic
(blood, diagnosis, immunology)
- Male
- Middle Aged
- ROC Curve
- Radioimmunoassay
(standards)
- Reference Standards
- Young Adult
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