Overt iron deficiency in sickle cell disease.

Overt iron deficiency was diagnosed in four patients with sickle cell disease. Three patients had homozygous SS and one had hemoglobin SC disease. The cause in each case was proved or suspected blood loss. Iron repletion was accompanied by increases in the blood hemoglobin and hematocrit levels, erythrocyte mean corpuscular volume, and mean corpuscular hemoglobin concentration (MCHC) and by change in the RBC morphologic characteristics from hypochromic microcytic to normochromic normocytic. The diagnosis of iron deficiency was confirmed by the finding of a low serum ferritin level, a high serum total iron-binding capacity, or both. Two patients who had had no painful crises while they were iron deficient began having crises again, and another patient had painful crises for the first time after the blood values improved. Whether a lowered MCHC is beneficial to patients with sickle cell diseases is an important but unanswered question.