Blood, 1960, Vol. 15, No. 1, pp. 36-44.
© 1960 American Society of Hematology, Inc.
A Quantitative Method for Measuring the Gastrointestinal
Absorption of Iron
JOHN D. BONNET 1,
ALBERT B. HAGEDORN 1, and
CHARLES A. OWEN JR. 1
1 Mayo Clinic and Mayo Foundation, Rochester, Minn.
A simple test is proposed for evaluating the gastrointestinal absorption of iron.
It begins with an oral dose of 50 µg. of stable iron labeled with 1 µc. of Fe59,
to which about 300 mg. of ascorbic acid are added. Feces are assayed for Fe59
until any single stool contains less than 1 per cent of the dose. Absorption is
determined on the assumption that all unrecovered Fe59 has been absorbed.
The test was designed to minimize handling of stools by assaying whole
specimens, and this process has the added virtue of increasing statistical accuracy of the measurement of radioactivity.
The main advantage of the procedure using a 50 µg. dose is that with it one
obtains a normal value for absorption which is about one-half of the dose.
This permits measurement of either increased or decreased iron absorption.
With our standard test method, 19 normal women absorbed an average
of 62 per cent of the dose and 22 normal men absorbed 40 per cent.
In addition to this sex difference, not explained by the difference in their
blood hemoglobin levels, there seemed to be a tendency toward reduced
absorption with greater age.
Preliminary results of this test in patients with hypochromic anemia and
steatorrhea are reported.
Increased absorption of iron followed the administration of ascorbic acid
whether the iron was in the ferric or the ferrous form. The concept that ferrous
iron is better absorbed by man requires re-evaluation.
Submitted on March 2, 1959
Accepted on July 12, 1959
