Usefulness of Cell Counter-Based Parameters and Formulas in Detection of β-Thalassemia Trait in Areas of High Prevalence

The present study aimed to retrospectively evaluate the usefulness of cell counter–based parameters and formulas in β-thalassemia trait (BTT) detection. The study included 170 BTT cases (hemoglobin [Hb]A 2 >4.0% [0.04]) and 30 non-BTT cases (HbA 2 , 2.3%3.5% [0.02-0.04]). Depending on the hemoglobin level and iron deficiency, the BTT group was further classified into classic BTT (n = 112) and BTT with iron deficiency anemia (n = 58). The RBC count, MCH, MCV, RDW, and Shine and Lal, Mentzler, Srivastava, England and Fraser, Ricerca, and Green indexes were applied. For the first time in the population of India, these 10 cell counter parameters and manual formulas were compared with high-performance liquid chromatography–derived HbA 2 levels for deriving a cost-effective alternative method; and receiver operating characteristic curves were applied. We found that the Shine and Lal, Srivastava, and Mentzler indexes, MCV, and MCH have better discriminative function than the RBC count and red cell distribution width and their related formulas. Thalassemia is a genetic disorder affecting synthesis of the globin moiety of the hemoglobin molecule. β-Thalassemia is prevalent in a broad belt extending from the Mediterranean basin to Southeast Asia. It is estimated that 1.5% of the world’s population carries β-thalassemia, ie, at least 80 to 90 million people with an estimated 60,000 new carriers born each year. The Southeast Asian region (which includes India, Thailand, and Indonesia) accounts for about 50% of the world’s carriers, ie, around 40 million people and almost half of homozygous births, whereas in the developed world, Europe and the Americas jointly account for just 10% to 13% of the world’s carriers. 1 The prevalence of β-thalassemia trait (BTT) is about 3.3% in India. In various parts of India, the prevalence of BTT is different: 6.5% in Punjab, 8.4% in Tamilnadu, 4.3% in south India, and 3.5% in Bengal. βThalassemia has a high prevalence in some communities, such as Sindhi, Luvana, Tribes, and Rajputs. The incidence of BTT in Gujarat is 10% to 15% in these communities, whereas the incidence in the general population is 2% to 3%. 2 Because a majority of people with BTT are asymptomatic, they may not be aware of their carrier state. BTT is associated with mild or no anemia but with reduced mean corpuscular volume (MCV) mean corpuscular hemoglobin (MCH) values and an elevated hemoglobin A 2 (HbA 2 ) level. The prevention of this homozygous condition can be