Author(s): Denic S, Agarwal MM, Al Dabbagh B, El Essa A, Takala M,
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Abstract Screening for β -thalassemia trait (BTT) relies on measuring hemoglobin (Hb) A2. Since multiple factors can affect HbA2 levels, the screening can become unreliable. In 1356 healthy Arabs enrolled into a federally funded premarital BTT screening program, the effects of iron deficiency (ID), α (+)-thalassemia trait, gender, smoking, and tribalism on HbA2 were studied. The complete blood count and hemoglobin fractions were determined on the entire cohort; serum ferritin (<15 μ g/L) in 391 subjects was used to determine ID. BTT was present in 29 (2.1\%) subjects (HbA2 > 3.5\%). Among 77(20.3\%) subjects with ID, the mean HbA2 (2.30 ± 0.23\%) was 0.2\% lower than in subjects without iron deficiency (2.50 ± 0.24\%, P < 0.0001). In 65 (38\%)/172 subjects with phenotypic α (+)-thalassemia trait, the mean HbA2 (2.43 ± 0.24\%) was 0.13\% lower than in subjects without α (+)-thalassemia trait, P < 0.0001. The mean HbA2 did not differ between males and females, smokers and nonsmokers, and between the tribes. Thus, 35 (2.6\%) subjects with HbA2 between 3.2 and 3.5\% were at a risk of false negative diagnosis of BTT. Since iron deficiency and α (+)-thalassemia are both common and both lower HbA2, modifications in screening recommendations for BTT are proposed.
This article was published in ISRN Hematol
and referenced in Hereditary Genetics: Current Research