Amplification of the combinational detection of antinuclear antibody and antinuclear antibodies spectrum in the diagnosis of autoimmune diseases

Autoantibody is an important diagnostic index of autoimmune diseases(AID).In order to investigate the diagnostic value of antinuclear antibody(ANA) and antinuclear antibodies spectrum(ANAs) in patients with AID,from October 2011 to December 2011,1 231 presumptive AID patients were chosen for research by the Xiamen Center of Clinical Laboratory.ANA and ANAs were detected with indirect immunofluorescence(IIF) and immumoblot test(IBT) respectively,while the initial dilution of IIF-ANA was 1:100.In this study,three testing programs were performed:the IIF-ANA,the IBT-ANAs,the combination of ANA and ANAs.The positive rates of IIF-ANA and IBT-ANAs were 33.63% and 34.85%,respectively.The positive rate of ANA and ANAs in combination was 43.05%,which was higher than IIF-ANA or IBT-ANAs along(P0.05).There were 116 patients(9.42%) with IIF-ANA 1:100(-)/IBT-ANAs(+),which were detected by IIF-ANA at the dilution of 1:32 and 1:10,and results showed that 103 patients were positive for IIF-ANA by 1:32 dilution,10 patients were positive by 1:10 dilution,and 3 patients were with negative by 1:10 dilution.The positive rates of IIF-ANA(1:32) and IIF-ANA(1:10) were 8.37% and 9.18%,respectively,which were higher than IIF-ANA(1:100)(P0.05),but there was not statistically significant(χ2=0.17,P0.5) between IIF-ANA(1:32) and IIF-ANA(1:10).We conclude that IIF-ANA can be used in the screening of AID.While simply testing of ANA or ANAs would lead to missed diagnosis of AID,combinational detection of ANA and ANAs will reduce the false negative rate,especially for those suspected cases with positive ANA by 1:32 dilution.