Low-dose oral iron absorption test in anaemic patients with and without iron deficiency determined by bone marrow iron content.

The low-dose oral iron absorption test (OIAT) was performed in 85 consecutive anaemic patients referred for bone marrow examination in order to investigate the ability of the test to predict bone marrow iron stores and to differentiate between different categories of anaemia. Eight patients were excluded for technical reasons. Test results from 77 patients are presented as Cmax (micromol/l): the maximum increase in S-iron measured during a 3 h period after administration of 10 mg oral iron sulfate. Iron deficiency was defined as the absence of stainable iron in bone marrow aspirates. Cmax was higher in 46 iron deficient patients [3 (median); 0 and 13 (1st and 3rd quartiles); 0-40 (range)] than in 31 non-iron-deficient patients (0; 0 and 2; 0-4) (P<0.01). 27 patients had primary bone marrow disease, 25 patients had absent bone marrow iron stores accompanied by inflammation, 17 patients had anaemia of chronic disease (ACD) and 8 patients had uncomplicated iron deficiency anaemia (IDA). Patients with IDA had higher Cmax (15; 13 and 28; 6-40) than patients with ACD (1; 0 and 2; 0-3), and than the 69 non-IDA patients (1; 0 and 3; 0-19) (P<0.001). Cmax values above 5 micromol/l always indicated absent bone marrow iron stores.