Repeat ANA Testing Holds Little Value

This study suggests that doctors may want to reconsider allowing repeat antinuclear antibody (ANA) testing. Repeat tests are expensive and hold little value, shows this study from The Lancet Rheumatology.

An Australian study published in The Lancet Rheumatology suggests there is little benefit in repeating an antinuclear antibody (ANA) test initially returned as negative.

ANA testing is frequently used as a diagnostic or screening test in patients who have inflammatory or musculoskeletal symptoms that may suggest the presence of an autoimmune condition, such as lupus, scleroderma, Sjögren’s syndrome, or juvenile arthritis, among others conditions.

However, the presence of antinuclear antibodies does not necessarily indicate the presence of an autoimmune condition or even the need for treatment. Autoantibodies occur naturally in the body and are present in small amounts in healthy individuals who do not have autoimmune disease.

In this study, which was led by Eric F Morand of Monash University School of Clinical Sciences in Australia, researchers evaluated the frequency, utility, value and cost of repeat ANA testing for the diagnosis of rheumatological conditions.

The study is based on an evaluation of 36,715 ANA test results that were conducted in 28,840 patients between 2011 and 2018.

From March 19, 2011, to July 23, 2018, a total of 36 715 ANA tests were done in 28 840 patients at a total cost of US$675 029 (2018 equivalent).

Repeating the test after a negative results proved to have little clinical value, but it was associated with substantial additional costs. In this study, the cost of 36,715 tests was $675,029 (U.S. dollars in 2018) and of these, 14, 058 (38.3%) were positive and 7,875 (21.4%) were repeats in 4,887 (16.9%) patients. Of these, 2,683 patients (54.9%) initially tested negative and and 2,204 (45.1%) intially tested positive.

Of the 2,683 who initially tested negative, 511 (19%) had a positive result when the test was repeated once in under two years. Still, a positive test result did not often lead to change in diagnosis. For example, of 451 patients who tested negative initially, but then positive after a repeat test, only five patients received a change in diagnosis.