Performance of the Microcytic Anaemia Support Tool (MAST) for optimizing iron therapy in resource-limited settings

Abstract

Anemia often results from overlapping causes, including nutritional deficiencies, inflammation, and hemoglobinopathies, complicating diagnosis and treatment in settings with limited diagnostic capacity. The Microcytic Anaemia Support Tool (MAST) predicts iron deficiency, functional iron deficiency, or thalassemia trait in individuals with microcytic anemia, from Sysmex hematology analyzer CBC-DIFF-RET data to guide iron therapy decisions. This study evaluated MAST as an alternative to empirical anemia treatment in a malaria-endemic rural community in Burkina Faso. MAST accuracy in determining iron treatment needs (immediate, delayed, or not indicated) was evaluated in cohorts with microcytic anemia, normocytic anemia, all anemias combined, microcytosis without anemia, and neither microcytosis nor anemia. Reference diagnoses were based on iron studies, cytokines, CRP, and hemoglobinopathy testing. Malaria testing was also performed. This retrospective study included 696 subjects aged ≥1 year without known illness. In the microcytic anemia cohort, MAST achieved 88.9% sensitivity and 79.5% specificity for reference iron treatment recommendations, identifying iron as inappropriate in 42.6% (66/155) while missing iron deficiency in 5.2% (8/155). Detection of iron deficiency was unaffected by subclinical malaria (83.7% vs 92.7%, p=0.304). Among 203 subjects with anemia due to inflammation or thalassemia, MAST correctly identified 90.1% (183/203) at risk of unnecessary empirical iron therapy. It also excluded thalassemia in 96.3% (289/300) of subjects without hemoglobinopathies. MAST showed high concordance with reference iron-treatment recommendations in microcytosis, with or without anemia, identified most non-iron-deficient cases, and may help avoid inappropriate iron therapy. Performance was unaffected by malaria supporting its use in resource-limited settings.