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Int J Clin Exp Pathol 2011;4(8):748-754

Original Article
Evaluation of a high avidity anti-dsDNA IgG enzyme-linked immunosorbent assay for the
diagnosis of systemic lupus erythematosus

Brenda B Suh Lailam, Tyson R Chiaro, Wayne Davis K, Andrew R Wilson, Anne E Tebo

ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT, United States; Department of Pathology, University of Utah School of
Medicine, Salt Lake City, UT, United States

Received September 27, 2011; accepted October 29, 2011; Epub October 30, 2011; Published November 31, 2011

Abstract: The high avidity (HA) anti-dsDNA IgG ELISA is considered highly specific for the diagnosis of systemic lupus erythematosus (SLE).
The main objective of this study was to determine the performance of this test with existing assays for detecting anti-dsDNA IgG antibodies as
well as assess its analytical characteristics. For method comparison studies, we investigated the correlation between the HA ELISA with 8
other assays for the detection of dsDNA IgG antibodies namely; six anti-dsDNA IgG ELISA, the Crithidia luciliae immunofluorescence test
(CLIFT) and an in-house developed Farr radioimmunoassay (RIA). Overall, 125 patient (100 ANA-positive, 25 CLIFT-tested) and 100 healthy
control samples were tested. The assay was also evaluated for imprecision, lot-to-lot consistency and the effect of interfering substances
using commercial quality control materials based on the manufacturer’s claims unless otherwise stated. Of the 100 ANA positive samples, 18
were positive in the HA ELISA with significant levels of antibodies in the six ELISAs and CLIFT. The HA ELISA had a specificity of 100% with an
overall agreement of 84% with the RIA. Intra- and inter-assay imprecision ranged from 13.9-16.5% and the reproducibility between lots based
on qualitative interpretation was 100%. Hemoglobin, bilirubin and lipemia showed variable interference with assay performance based on the
manufacturer’s claims and our in-house protocol. Our data suggest that the HA ELISA although less sensitive than the other dsDNA IgG
assays evaluated, is specific and predicts high levels of anti-dsDNA IgG antibodies.
(IJCEP1109010).

Keywords: Performance, agreement, imprecision, anti-dsDNA, antibodies

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E-mail: anne.tebo@aruplab.com