The usefulness of serum transferrin receptor and ferritin for assessing anemia in rheumatoid arthritis: comparison with bone marrow iron study

Objectives. This study was aimed at investigating the usefulness of serum transferrin receptor (sTfR) and ferritin in anemic patients with rheumatoid arthritis (RA) compared with bone marrow storage iron and other tests for anemia. Methods. Fifty-five anemic RA patients underwent anemia study. Bone marrow iron stain was performed in 18 patients. sTfR and serum ferritin levels were compared with bone marrow iron stores. Results: (1) Mean sTfR concentration was 2.63 +/- 1.91 mg/L, (2) sTfR correlated with most indicators of anemia, (3) sTfR showed no correlation with CRP and ESR, whereas ferritin did, and (4) sTfR was higher in the "iron depleted" subgroup than in the "iron nondepleted" subgroup in bone marrow study. Conclusion. The measurement of sTfR and Ferritin is useful in finding the cause of anemia in RA and is a possible substitute for invasive bone marrow iron study.