Background: Many formulas from red blood cell (RCB) indices are instructed to differentiate between iron deficiency anemia (IDA) and beta thalassemia trait. None had 100% Youden index.
Aim of the work: To introduce two new formulas and evaluate them in the differentiation between IDA and beta thalassemia trait in adults Saudi (male and female; male; female) in the Makkah region. Furthermore, to evaluate the previous formulas in our population.
Methods: A total of 249 participants, 91 with IDA, 123 with beta thalassemia trait, and 35 healthy persons. All subjected to complete blood count, measurement of iron profile, hemoglobin electrophoresis and hemoglobin A2 by column chromatography. The first new formula equal hemoglobin (Hb) + hematocrit (Hct) + RBC and second equals Hb + Hct + RBC-red cell distribution (RDW). The previous formula used is England and Fraser, Mentzer, Strivastava, Ehsani, Green and King, red cell distribution index, Ricerca, and Shine and Lal Results: In both men and women, the England and Fraser was the best with a Youden's index of 70.4%, followed by Green and King 67.4%. In men, the England and Fraser and our new formula 1 had the highest Youden' index 84.7% and 84.1%, respectively. In women, the England and Fraser and RDW index had the highest Youden' index 74% and 69.2%, respectively.
Conclusion: The England and Fraser and our new formula 1 are the best formulas in men. The England and Fraser and RDW index are the best formulas in women.
Keywords: Beta thalassemia trait; Iron deficiency anemia; Red blood cell indices.