Analysis on detection results of different dilution titers of antinuclear antibodies in children / 国际检验医学杂志

ABSTRACT

Objective To compare the influences of different dilution titers on the ANA detection by the indirect immunofluores‐cence assay(IIF) in children for investigating the necessity of reducing serum initial dilution titer .Methods Serum ANA was detec‐ted by using the indirect immunofluorescence assay at a serial of dilution titer in 110 healthy controls and the results were compared with the results of specific ANAs by the linear immunoassay (LIA);meanwhile the ANA‐LIA results in clinical children patients with ANA‐IIF negative were also analyzed .Results With the dilution titers gradual decrease from 1∶80 ,1∶40 and 1∶20 in the samples of the health group ,the positive detection rates of ANA‐IIF were risen ,which were 7 .3% ,9 .1% and 10 .9% respectively , but the differences were not statistically significant (P>0 .05) ,the weak‐positive rates were 7 .3% ,15 .5% and 31 .8% respective‐ly ,the differences were statistically significant (P<0 .01) .Among 110 healthy children under going the physical examination ,the specific ANA was detected out in 8 samples ,the positive rate was 7 .3% .Among 8 positive cases at the dilution titer of 1∶80 by the IIF method ,specific ANA was in 2 cases;in 4 added cases of fluorescence ANA positive samples at the dilution titers of 1∶40 and 1∶20 ,specific ANA was in 1 case .If with any positive of ANA‐IIF(1∶80) or ANA‐LIA as the ANA positive ,the ANA positive rate was risen from 7 .3% to 12 .7% .In the clinical samples among 29 cases of ANA‐IIF(1∶80) negative autoimmune liver disease related autoantibody detection ,the specific ANA‐LIA positive was detected in 5 cases (17 .2% ) .Conclusion Reducing the initial ti‐ter of children serum is unable to obviously increase the ANA‐IIF positive detection rate ,on the contrary increases the non‐specific weak positive .Therefore ,clinical laboratory does not change the dilution titer of children routine ANA sample .The detection by combining with the specific ANA‐LIA spectrum is conducive to find ANA .