A mode of error: Immunoglobulin binding protein (a subset of anti-citrullinated proteins) can cause false positive tuberculosis test results in rheumatoid arthritis

BiP naturally found in the majority of ACPA-positive RA patients can result in a false positive QFT-G TB. Subsequent undertreatment of RA, if biologic therapy is withheld, and overtreatment of presumed latent TB may harm patients.