Evaluation of Applying a Combination of Red Cell Indexes and Formulas to Differentiate β-Thalassemia Trait from Iron Deficiency Anemia in the Thai Population

Abstract

Red cell indexes and formulas have been established as simple, fast, and inexpensive tools to differentiate β-thalassemia (β-thal) trait from iron deficiency anemia. However, none of them showed 100.0% sensitivity and specificity. Moreover, one index may show greater sensitivity and specificity in one population but is ineffective in another population. This study evaluated the diagnostic reliability of a combination of two red cell indexes [red blood cell (RBC) and red blood cell distribution width (RDW)] and nine formulas called ‘11T score’ for differentiation of β-thal trait and iron deficiency anemia in the Thai population. A total of 103 cases, 67 β-thal trait and 36 iron deficiency anemia, Thai subjects with microcytic hypochromic anemia [mean corpuscular volume (MCV) <80.0 fL and mean corpuscular hemoglobin (Hb) (MCH) <27.0 pg] were involved in this retrospective study. The results showed that the 11T score with a cutoff value of 7 was able to discriminate between β-thal trait and iron deficiency anemia with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and efficiency (EFF) higher than 70.0%. It also had 85.4% of correctly identified cases and the highest value of Youden’s Index (YI) (73.8%) when compared to the 11T score with other cutoff values (5, 6, 8 and 9) and other indexes. Thus, the 11T score with the cutoff value of 7 could be used to differentiate β-thal trait from iron deficiency anemia in the Thai population.

Keywords:

• β-Thalassemia (β-thal)
• formulas
• iron deficiency anemia
• microcytic anemia
• 11T score

Acknowledgements

The authors thank the technicians at the Associated Medical Sciences Clinical Service Center, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand for their assistance. We are also grateful to Kallayanee Treesuwan Rock, Clinical Service Center, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand, for refinement of the English language.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.