Antinuclear antibody testing in a Turkish pediatrics clinic: is it always necessary?

Abstract

Introduction The term anti-nuclear antibody (ANA) is used to define a large group of autoantibodies which specifically bind to nuclear elements. Although healthy individuals may also have ANA positivity, the measurement of ANA is generally used in the diagnosis of autoimmune disorders. However, various studies have shown that ANA testing may be overused, especially in pediatrics clinics. Our aim was to investigate the reasons for antinuclear antibody (ANA) testing in the general pediatrics and pediatric rheumatology clinics of our hospital and to determine whether ANA testing was ordered appropriately by evaluating chief complaints and the ultimate diagnoses of these cases. Methods The medical records of pediatric patients in whom ANA testing was performed between January 2014 and June 2016 were retrospectively evaluated. Subjects were grouped according to the indication for ANA testing and ANA titers. Results ANA tests were ordered in a total of 409 patients during the study period, with 113 positive ANA results. The ANA test was ordered mostly due to joint pain (50% of the study population). There was an increased likelihood of autoimmune rheumatic diseases (ARDs) with higher ANA titer. The positive predictive value of an ANA test was 16% for any connective tissue disease and 13% for lupus in the pediatric setting. Conclusion in the current study, more than one-fourth of the subjects were found to have ANA positivity, while only 15% were ultimately diagnosed with ARDs. Our findings underline the importance of an increased awareness of correct indications for ANA testing.

Antinuclear Autoantibodies in Health: Autoimmunity Is Not a Synonym of Autoimmune Disease

“…Similar results were obtained by Turkish researchers [ 100 ]. Of the 409 examined children with suspected systemic ADs with non-organ-specific autoantibodies who lived in Turkey, 27.6% had positive ANA titers, and only 15% were ultimately diagnosed with ADs.…”

“…At the same time, although there is some evidence confirming that ANA can also be detected in patients with rheumatic diseases long before their clinical manifestations [ 97 , 98 , 99 ], ANA-positive patients do not necessarily develop ADs in the follow-up, at least for those diseases which are generally recognized as autoimmune ones [ 100 , 101 , 102 ].…”

“…None of the 13 patients with an ANA titer of less than 1/160 had rheumatic diseases. The positive predictive value of ANAs was 16% for any systemic AD and 13% for SLE [ 100 ].…”

“…However, for the diagnosis of SLE, detection of ANAs is more significant, since the disease is usually characterized by higher levels of autoantibodies [ 171 , 172 ]. However, even for SLE, the diagnostic value of ANAs in the studies cited above did not exceed 15% [ 100 , 151 ].…”

Prevalence of anti-nuclear autoantibodies (ANA) in the general Polish population - analysis of the influence of sex and age on the variability of ANA.

“…It is well known that SARDs mainly affect older people, and predominantly women [2][3][4][5]. At the same time, there are increasing cases of connective tissue diseases in young people and even in children [6][7][8]. Thus far, the etiology of anti-nuclear antibody (ANA) formation has not been fully elucidated.…”