Oral Iron Absorption Test as a Predictor of Response to Oral Iron Therapy and Gastrointestinal Malabsorption...

Iron deficiency anemia (IDA) affects approximately 2 billion individuals globally, yet optimal response to oral iron supplementation remains unpredictable. The oral iron absorption test (OIAT) represents a potentially valuable diagnostic tool for predicting therapeutic response and identifying underlying gastrointestinal malabsorption syndromes.

This prospective study enrolled 190 IDA patients at a tertiary care center. After collecting baseline hematological parameters, participants underwent OIAT by receiving 60 mg of elemental iron, with serum iron levels measured at baseline and after 2 hours. Patients with abnormal OIAT results underwent additional investigations to identify underlying malabsorption syndromes.

Among the participants (mean age 32.34 ± 11.84 years, 90.5% female), 34.2% demonstrated abnormal OIAT results. Malabsorption was diagnosed in 19.5% of subjects, with Helicobacter pylori infection (54.1%), autoimmune gastritis (27.0%), and celiac disease (18.9%) as the predominant etiologies. OIAT showed excellent sensitivity (89.2%), good specificity (79.1%), and exceptional negative predictive value (97.6%) for identifying malabsorption syndromes.

OIAT demonstrates robust diagnostic performance for predicting response to oral iron therapy and identifying malabsorption syndromes in IDA. The high negative predictive value positions OIAT as an effective first-line screening tool, potentially reducing the need for invasive investigations in patients with normal test results.