Cobalt excretion test as index of iron absorption and diagnostic test for iron deficiency.

A cobalt excretion test was performed in 50 patients with various, mainly hematologic, disorders and was found to be an accurate and easily obtainable index of iron absorption. The test was found to be of very limited value in predicting iron stores. The cobalt excretion test may have some usefulness as a simple, apparently safe, noninvasive test for identification of persons with iron depletion resulting from uncomplicated blood loss. However, in more complex circumstances, it fails to differentiate iron deficiency anemia from anemia due to other causes.