CLINICAL-EVALUATION OF VARIOUS SELECTED ELISA KITS FOR THE DETECTION OF ANTI-DNA ANTIBODIES

Fifty four coded sera, 38 from eight patients with systemic lupus eryt hematosus (SLE), four from one patient with systemic vasculitis, one f rom one patient with polyarthritis and 11 normal controls were tested for anti-dsDNA antibodies using seven commercial enzyme linked immunos orbent assays (ELISA) and the radioimmunoassay method (RIA) routinely used in our unit. Sensitivity, specificity and predictive values were tested for both SLE diagnosis and disease activity. Using anti-dsDNA a ntibodies as a diagnostic test for SLE there were differences in sensi tivity (from 66% to 95%), specificity (from 75% to 100%, predictive po sitive values (from 89% to 100%) and predictive negative values (from 50% to 87%) among ELISA kits. The RIA method was either more specific or equal to ELISA kits. Using 'equivocal' values as positive values an increase in sensitivity was observed but at the expense of specificit y. Similar differences and trends were observed when the results were used as a measure for disease activity. This suggests that there are d ifferences in sensitivity, specificity and predictive values among ELI SA kits both in the diagnosis of SLE as well as in the determination o f disease activity.