Cobalt test for the detection of iron deficiency anemia.

Abstract

A test to detect iron deficiency anemia is based on the 6-hour urinary excretion of oral 57Co. The mean excretion in 25 healthy control subjects 31 to 75 years of age with stainable iron in the marrow was 7.3% (range, 4% to 11%). Twenty-six patients with iron deficiency anemia excreted more than 12% of the dose, whereas 30 patients with anemia from other causes excreted less than 11%. Cobalt excretion was also markedly increased in subjects who had iron deficiency without anemia and moderately increased in nonanemic subjects with recent blood loss, even when stainable iron was present in the marrow. The cobalt test does not supplant simpler diagnostic techniques, but it does provide the clinician with a practical alternative to bone marrow aspiration in the differential diagnosis of iron deficiency anemia. It is particularly applicable in mild iron deficiency anemia and in differentiating iron deficency anemia from anemia due to other causes.