Serum ferritin levels may be elevated in patients who have both iron deficiency and chronic inflammation, making the distinction between iron deficiency anemia and the anemia of chronic disease difficult. Mulherin et al developed a simple algorithm based on simple laboratory measures to help diagnose anemia in patients with rheumatoid arthritis.  The authors are from Dublin, Ireland.

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.)



(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.

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