Retrospective analysis of antinuclear antibody test results of 102 651 specimens

Objective To explore the positive distribution trend of the anti-nuclear antibodies (ANA) in outpatients and its significance in patients with autoimmune disease(AID). Methods The ANA in 102 651 specimens were measured by indirect immunofluorescence (IIF)from department of clinical laboratory, Peking Union Medical College Hospital from 2004 to 2008 (male: female; 1: 3, mean age;41 years old). Three thousand sixty-four cases with AIDS were chosen, which consist of 1 757 SLE, 250 SS, 518 RA, 150 PM/DM, 171 SSc, 108 PBC, 44 AIH and 66 AS. Meanwhile, the diseases control group was consist of 560 cases from 452 patients with inflammation and 108 patients with tumor. The positivedistribution of ANA, titre and fluorescence pattern in gender groups, age groups(≤ 20 years old,21-49 years old,≥50 years old) , and diseases groups were investigated, and the values of the results for AIDS diagnosis were evaluated. Results Of the 102 651 specimens, the positive rate of ANA was 49%. The positive rates for male patients and female patients were 26% and 56% respectively. The positive rate in female patients was statistically higher than that in male (χ~2 =6 652. 84,P<0. 01). In the different age group of ≤20 years old , 21-49 years old and≥50 years old, there was statistical significance of ANA positive rate (46% , 50% ,47% ,χ~2 = 108. 68, P < 0. 01 ) . The results indicated that the major pure fluorescence patterns were speckled pattern (34% ) and homogenous pattern ( 16% ) , and the major mix fluorescence pattern was speckled pattern/homogenous pattern (16% ). The major pure fluorescence pattern was speckled pattern in SLE, SS, RA, PM/DM(32% , 40% , 28% , 31% ), membranous pattern and centromere pattern in PBC (36% , 14% ). The positive rate of ANA was 82% in AIDS patients, and reach up to 94% in SLE patients whereas the positive rate of ANA in control group was 13%. There was statistical significance of the ANA positive rate between AIDS group and control group (χ~2 =1 114. 15 ,P <0. 01). The titers of ANA in patients with AID were predominantly above 1: 160 and less than 1: 80 in control group. Conclusions The positive rates of ANA in outpatients are different in term of gender and age. The positive rates and titers of antibodies are varied among different AIDS patients. The clinical laboratorians should pay attention to the value of ANA titer in AIDS diagnosis. In addition, the fluorescence pattern represents the diversity. There exists one-sidedness for diagnosis of AIDS depending on the fluorescence pattern, although some specific fluorescence pattern could provide some important diagnostic information for AIDS. Key words: Antibodies;  antinuclear;  Autoimmune disease;  Immunofluorescence antibody technique;  indirect;  Titer