Algorithm of Mulherin et al for the Diagnosis of Iron Deficiency Anemia vs Anemia of Chronic Disease in a Patient with Rheumatoid Arthritis

Step 1: Does the patient have rheumatoid arthritis? (If "yes" proceed, else stop).

Step 2: Is the patient anemic? (for males, hemoglobin < 11 g/dL; for women, hemoglobin < 10.5 g/dL)

Step 3: Is the serum ferritin < 40 µg/L? (If "no", proceed to Step 4; if "yes", iron deficiency.)

Step 4: Is the MCV > 85 fL? (If "no", proceed to Step 5; if "yes", anemia of chronic disease).

Step 5: Is the percent iron saturation < 7%? (If "no", anemia of chronic disease; if "yes", iron deficiency.)

Observations:

(1) The algorithm should be applicable to other patients with autoimmune disease.

(2) The age range for the patients was 20 to 80 years.

(3) The study involved 45 patients. I would be interested to see the algorithm validated in a larger group, and to see whether any of the patients classified as anemia of chronic disease responded to iron therapy.