By comparing the consistency of indirect immunofluorescence assay (IIFA), Immunoblot (IB), multiple microbead immunoassay (MBI) in the detection of antinuclear antibodies (ANA), and by comparing IB and MBI in the detection of ANA spectrum, the advantages and limitations of each method were evaluated to provide suggestions for clinical practice.

We collected serum samples from 578 patients who detected ANA by three methods since suspected of autoimmune disease. The consistency analysis of several methods was performed using the Kappa test.

Among 578 serum samples, the numbers of ANA-positive samples were 280 (48.4%), 225 (38.9%), and 252 (43.6%) by IIFA, IB, and MBI, respectively. The consistency of any two methods was above 85%, and the Kappa values above 0.7. Among them, the consistency of IIFA and IB was the strongest, and the Kappa value was 0.808 (95% CI:0.761~0.855). For ANA spectrum detection, the consistency was higher than 90% by IB and MBI, and the Kappa values ranged form 0.535 and 0.839. The most consistent antibody types were anti-SSA antibody and anti-Jo1 antibody, which were 0.839 and 0.832, respectively.

The above three methods have high consistency in detecting antinuclear antibody, among which indirect immunofluorescence method has the highest positive rate, indirect immunofluorescence method has the strongest consistency with western blotting method, and western blotting method has high consistency with multiple microbead immunoassay for detecting antinuclear antibody. To improve the diagnosis of autoimmune diseases and avoid missed diagnosis, the three methods should be combined for ANA detection in clinical practice.