Urinary iron in patients with sickle cell anamia.

Urinary iron excretion was measured in patients with sickle cell anemia and relateddiseases. Iron concentration in urine was determined by atomic absorption spectrophotometry and daily total iron excretion was calculated from this and total daily urine volume. Normal subjects excreted a mean of 88 pg Fe per day (95 per cent confidence limitsof 0 to 120 pg). Nine persons with sickle cell trait had normal Fe excretion rates.However, abnormally high iron excretion was present in the first urine sample obtainedfrom 27/31 patients with SS, 3/7 with SC, 1/2 with CC, and 1 with S-thalassemia. Iron excretion varied very significantly from day-to-day in individual patients. The results of studies attemting to relate this to increase excretion during activityas compared to rest were negative. No clear relationship of iron excretion to painfulcrisis could be shown, but remarkable rises in urine iron occurred in two patients who developed a hyperhemolytic crisis. These studies suggest that urinary iron reflects intravascular hemolysis primarily. No correlation was evident between urine iron and the patients' age, transfusion history, or serum iron values suggesting increased urinary iron excretion cannot be attributed to iron overload in sickle cell anemia.