ACR Tracking Concerns about ANA Testing Results
August 19, 2009
The ACR is still tracking concerns about ANA test results. Members alerted the ACR about concerns regarding the results of the antinuclear antibody test. This test is used to help screen for systemic lupus erythematosus, drug-induced lupus, and other diseases. Some ACR members are reporting false positives and negatives. Accurate results are crucial because treatment is determined according to the results of the test.
The immunofluresence methodology test to screen for ANAs is still available for use, and the ACR ANA taskforce is advising clinicians to continue using this test—rather than solid phase assays—as it believes it to be the best way to screen for ANAs.
Immunofluoresence Methodology Still Available In the Detection of Antinuclear Antibodies
The immunofluresence methodology test to screen for ANAs is still available for use, and the ACR ANA taskforce is advising clinicians to continue using this test—rather than solid phase assays—as it believes it to be the best way to screen for ANAs. During the past decade, commercial clinical laboratories have adopted a wide variety of new tests, including solid phase assays, for the detection of antinuclear antibodies. Some commercial laboratories have adopted these new assays to replace traditional “gold standard” indirect immunofluorescence tests to screen for ANAs. The new solid phase assays detect up to 13 specific autoantibodies, while indirect immunofluorescence using Hep-2 cell substrate detects more than 100 clinically-relevant autoantibodies, which is why the task force is making its recommendation.
Over the past two years, the ACR ANA Taskforce (which was established as a result of the growing concerns ACR members had over this topic) has carefully reviewed the available literature concerning newer, solid phase assays for the detection of ANAs. These solid phase assays were developed to detect a limited number of specific autoantibodies in the serum of patients with autoimmune diseases. Although some of these tests have been approved by the FDA for use in screening for antinuclear antibodies, the taskforce did not find sufficient evidence to conclude that solid phase screening assays are equivalent to indirect immunofluorescent assays for the detection of antinuclear antibodies.
The taskforces is alerting the membership that ANA by IFA is still available. The code for Quest is 38318. Quest has another test ANA choice (tm) 19946, but this is a solid assay, and it is not recommended as a screening test for ANAs. LabCorp also has an ANAIFA code (164947).
For more information about this topic, read “Know Your Labs” in the February 2009 issue of The Rheumatologist 
or read the ACR's position paper encouraging commercial laboratories to utilize the IFA test to detect ANA. You can also join the conversation by joining the ACR's advocacy listserve or contact the practice advocacy department at (404) 633-3777.
