Evaluation of Commercial Enzyme Immunoassays Compared to Immunofluorescence and Double Diffusion for Autoantibodies Associated with Autoimmune Diseases

Abstract

A commercially available enzyme immunoassay system for detecting autoantibodies to double-stranded DNA, deoxyribonucleoprotein, Smith, ribonuclearprotein, Sjögren's syndrome-associated antigens A and B, and scleroderma-associated antigen 70 was compared to the conventional immunofluorescence assay for double-stranded DNA and double diffusion assays for extractable nuclear antigens. There was excellent correlation between methods, but it appears that the enzyme immunoassays are more sensitive. Based on the results of this study, the authors recommend performing anti-nuclear antibody screening at two dilutions, with enzyme immunoassay follow-up of appropriate patient sera that are positive on anti-nuclear antibody testing. Nucleolar and centromere pattern anti-nuclear antibodies are diagnostic for variants of scleroderma and need no further evaluation. Negative anti-nuclear antibody tests performed using HEp-2 tissue culture cells require no further evaluation.

Autoantibody Testing for Connective Tissue Diseases:Comparison of Immunodiffusion, Immunoblot, and Enzyme Immunoassay

“…Few studies have compared the sensitivity and specificity of the newer methods with standard methods. [3][4][5] Most reports do not include clinical information.…”

The use of laboratory tests in the diagnosis of SLE

“…An assay should be accurate and produce the same result as other assays on all serum samples to enable comparison between diVerent centres. An international reference preparation (IRP) for anti- [33][34][35][36] CLIF is less likely than ELISA to detect low aYnity anti-dsDNA of uncertain clinical relevance, [37][38][39][40][41][42] especially if IgG specific conjugates are used. Local validation of each assay is essential to ensure adequate diagnostic performance.…”

Evaluation of a line immunoblot assay for detection of antibodies recognizing extractable nuclear antigens

“…Other investigators who have compared monospecific ENA antibody EIA results and ID results also reported a small percentage of discordant EIA-positive/ID-negative result sets (8,(10)(11)(12). Because some patients with discordant results exhibited clinical characteristics consistent with connective tissue diseases (10,12) it has been suggested that EIA may be more sensitive than ID, and should replace ID as the gold standard for ENA antibody detection.…”

“…Because some patients with discordant results exhibited clinical characteristics consistent with connective tissue diseases (10,12) it has been suggested that EIA may be more sensitive than ID, and should replace ID as the gold standard for ENA antibody detection. Unfortunately, this issue could not be addressed in this study, since all specimens were referred to MRL from other laboratories, and complete clinical information was not available.…”