Objective To develop a new method for detection of anti-dsDNA antibodies Methods Plasma double stranded DNA were used as antigen substrate and derived with fluorescence thiazole orange homodimer Capillary electrophoresis with laser induced fluorescence was used for the detection of anti dsDNA antibodies of patient with Systemic lupus erythematosus (SLE) Results 23 out of 40 patients with SLE were positive(57 5%); 1 out of 25 patients with other autoimmune disease were positive; none of 45 controls were positive Comparison of this assay with Farr and dot immunobinding assay(DIBA)shows that CE LIF was more sensitive than DIBA and more specific than Farr Conclusions The assay was rapid, simple and reproducible CE LIF may become a routine assay for determination of anti dsDNA antibodies