Evaluation of five commercial kits to detect dsDNA antibodies.

Experiments were performed to evaluate five commercial kit assays used for the detection of antibodies to dsDNA. The kits were compared using a performance index score as recommended by the guidelines of the European Committee for Clinical Laboratory Standards. The highest performance score was obtained using the radioimmunoassay from Immunodiagnostic Services Ltd, with the Amersham kit second, the immunofluorescence test using Crithidia luciliae third, the Walker ELISA kit fourth, and the haemagglutination assay fifth. The results showed that none of the kits was outstanding, each appeared to detect a different anti-DNA antibody type as different results were obtained using each kit in assays of quality control sera, linearity of the method, antibody detection in various patient groups, and interference by various substances. It is suggested that laboratories using commercial assay kits for the detection of antibodies to dsDNA should decide which is the most appropriate to their particular needs and that a performance index scoring system may be useful in the comparison of assay evaluations between different laboratories.