Assessment of Optimal Screening Tests for the Detection of an Inflammatory Myositis-associated Interstitial Lung Disease

Background Interstitial lung disease (ILD) is a common pathologic consequence of the idiopathic inflammatory myopathies, and it may be the initial presentation of autoimmune disease in many cases. There are no well-established guidelines to direct the evaluation of this disease in these cases. This study looked at the utility of four common serologic tests to screen for a myositis-associated ILD. Methods This is a single institution retrospective analysis of four common serologic tests (antinuclear antibody [ANA], creatine kinase [CK], aldolase, and anti-Sjögren's syndrome A [anti-SSA]) to detect a positive antibody on an extended myositis antibody panel. Results The serum aldolase was the most sensitive test to detect the presence of a positive antibody on an extended myositis antibody panel with a sensitivity of 54.5%. The anti-SSA was the least sensitive at 21.4%. A positive result for anti-SSA antibodies was associated with a 100% positive predictive value when all other screening tests (ANA, aldolase, and CK) were also positive. Conclusion No single screening test was sufficient for the evaluation of a myositis-associated ILD. A positive serum aldolase had higher sensitivity, and a positive SSA had a high positive predictive value when other screening markers were also elevated, but clinicians still need to maintain a high index of suspicion for myositis-associated ILD.