To determine if patients with seropositive rheumatoid arthritis (RA) have abnormally elevated concentrations of cardiac troponin-I (cTnI). Reports suggest the presence of serum rheumatoid factor (RF) may interfere with the cTnI assay, leading to falsely elevated cTnI levels. One study reported a falsely elevated cTnI in 15 out of 100 serum samples with elevated RF using the Abbott assay, but no elevated level using the Bayer assay. It is unclear how many of these samples came from patients with RA.
Serum samples were drawn from 60 patients with seropositive RA. We measured RF and cTnI levels using both the Abbott AxSYM assay and the Bayer ADVIA Centaur assay.
Of 60 RA patients with RF ranging from 15 to 2724 IU/ml, none was found to have an elevated cTnI on either assay.
Using 2 commercial assays for cTnI, we found that patients with seropositive RA do not have falsely elevated serum cTnI levels.