Use of diethylenetriamine penta-acetic acid (D.T.P.A.) in the clinical assessment of total body iron stores

As a quantitative test of iron storage the six-hour urinary excretion of iron was measured after the intravenous infusion of the iron-chelating agent diethylenetriamine penta-acetic acid (D.T.P.A.). The value of this test in determining the presence and magnitude of the total body iron stores was assessed in patients with diseases of iron storage. In patients with idiopathic haemochromatosis and in their first-degree relatives with increased iron stores as measured by hepatic biopsy, the result of the D.T.P.A. test fell progressively as iron stores were reduced by venesection therapy. There was a significant correlation between the result of the D.T.P.A. test and the excess iron storage as measured retrospectively by the effects of venesection therapy, and also between the D.T.P.A. test and the unsaturated iron-binding capacity (U.I.B.C.) in these patients. In patients with excess iron stores due to diseases other than idiopathic haemochromatosis (e.g., alcoholic cirrhosis, haemochromatosis associated with refractory anaemia) the D.T.P.A. test demonstrated the presence of excess iron stores, but the results were very variable and did not correlate closely with the U.I.B.C. or the degree of hepatic haemosiderin deposits. Unexpectedly high results for the D.T.P.A. test were found in some patients with iron-deficiency anaemia.