An evaluation of commercial kits for the detection of antibodies to double-stranded DNA.
Antibodies to double-stranded (ds) DNA may provide useful information in the management of patients with systemic lupus erythematosus. commercial radioimmunoassay (RIA) kits for the detection of (ds) DNA antibodies (Lupo-Tec, Wampole Laboratories; anti-DNA kit, Amersham Corporation) were compared with a modified Farr assay and checked for intra-lot, inter-lot and inter-assay variation. Purity of DNA preparations was assessed using rabbit antibody to single-stranded (ss) DNA. Selected sera with low (less than or equal to 15%), moderately elevated (less than or equal to 40%), or markedly elevated (greater than or equal to 44%) (ds) DNA binding values (Farr assay) were tested. Positive and negative control sera when supplied with the kits also were evaluated. Normal sera were used as internal controls. A variable degree of intra-lot, inter-lot, and inter-assay correlation was observed. At low antibody levels, discordance was observed but values greater than or equal to 25% (Farr assay) were abnormally elevated in all kits tested. Clinical and laboratory personnel should be aware of potential pitfalls in RIA methods and carefully interpret results when commercial DNA kits are used.
D000974:Antibodies, Antinuclear / Q000032:analysis; D001323:Autoantibodies / Q000032:analysis*; D004247:DNA / Q000276:immunology*; D005069:Evaluation Studies as Topic; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D011863:Radioimmunoassay / Q000295:instrumentation; D011933:Reagent Kits, Diagnostic
D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D011933:Reagent Kits, Diagnostic; D004247:DNA