Red cell indices and formulas have been established as simple, fast, and inexpensive means for discrimination between the β-thalassemia (β-thal) trait and iron deficiency. However, there were no reports of the diagnostic reliability of different red cell indices and formulas in discrimination of β-thal trait from iron deficiency in the Thai population. The aim of this study was to examine the diagnostic accuracy of five red cell indices [red blood cell (RBC) count, mean corpuscular volume (MCV), mean corpuscular hemoglobin (Hb) (MCH), mean corpuscular Hb concentration (MCHC), and red cell distribution width (RDW)] and eight formulas (Sirdah, Green & King, RDW Index, Menzler, England & Fraser, Ehsani, Srivastava, and Shine & Lal). Their sensitivity, specificity, positive and negative prognostic value and efficiency, were analyzed in 77 Thai school children, 21 with the β-thal trait and 56 with iron deficiency. The Sirdah and Srivastava formulas proved to be the most reliable indexes as they had 100.0% sensitivity and negative predictive value, the highest efficiency (97.4%), and the highest Youden's Index value (96.4%). Therefore, these formulas could be used in initial discrimination of the β-thal trait from iron deficiency in Thai school children.
Keywords: Thai school children; formulas; iron deficiency; red cell indices; β-Thalassemia (β-thal).