ABSTRACT
ObjectiveTo establish an analytical method with high sensitivity and wide range in biotin-avidin and time-resolved fluoroimmunoassay system for the quantitative detection of antinuclear antibody (ANA)-Ig (GAM).MethodsANA in standard preparation or sample was combined with solid nuclear antigen,biotinylation antibody and the europium(Eu3+)-labelled avidin to form the compounds of solid nuclear antigen-antibody-biotinylation antibody-SA-Eu3+.The fluorescence enhancement fluid was added to dis-sociate the Eu3+,the content of ANA was directly proportional to fluorescence intensity,the BAS-TRFLA was established for the quantitative detection of ANA-Ig (GAM).The sensitivity,specificity,reliability and range of detection were evaluated.Semm of 50 blood donor,105 patients with systemic lupus erythematosus (SLE),109 patients with rheumatoid arthritis(RA),25 patients with PBC,29 patients with Sj(o)gren's syndrome (SS),23 patients with scleroderma,25 patients with MCTD were included in this study.The positive rate was calculated.ResultsThe inner-group difference between high,medium and low densities mixture serum was 3.13％,3.74％ and 5.76％ and the inter-group precision rate was 5.31％,6.25％ and 7.46％ in BAS-TRFLA.The sensitivity of TRFIA was better than that of the ELISA method.The low detection limit was 2.24 U/ml.The mean recovery rate was 100.74％.The results measured by the TRFIA and ELISA methods were closely correlated(R2=0.978).The positive rate of blood donor,and patient with SLE,RA,PBC,SS,scleroderma and MCTD were 0,100％,23％,96％,38％,91％,92％ respectively.When compared with ELISA,the detection range of TRFIA was wider,and stability was better.ConclusionBAS-TRFIA is a stable method for detection of ANA with high sensitive and wide range of detection.It is important for the early diagnosis of autoimmune disease and monitoring the treatment efficacy of autoimmune disease.And this method may be widely used in clinical laboratories in the future.