HbA2 and Fetal haemoglobin in the diagnosis of Thalassemia and Hemoglobinopathies

Abstract

Background: Hemoglobin (Hb) disorders which include hemoglobinopathies and Thalassemia affect 7% of the world population. Capillary electrophoresis is useful for screening and follow up of Hb disorders . Aim:To evaluate HbA2 and HbF (fetalhemoglobin) in the diagnosis of Thalassemia and hemoglobinopathies.Material and Methods: 100 consecutive Capillary Hemoglobin electrophoresis done as a part of screening programme for Hb disorders from Jan2016 to june 2016 was included in the study. Children <1 yr of age and individuals with recent blood transfusion were excluded . Hb, RBC count and MCV were recorded.Results: Of the 100 Hb electrophoresis performed, 57 normal and 43 abnormal patterns were seen. Among the abnormal Hb patterns, β thalassemia trait (βTT) was the most common constituting 58.2% followed by Sickle cell (HbS) trait(11.7%), HbE trait(9.3%) and HbE/ β Thalassemia (7.0%). The HbA2 levels in normal, βTT, Sickle cell trait , HbE trait and HbE/ β thalassemia were 2.12%(SD 0.5), 4.9%(SD 0.62), 3.28%(SD 0.43), 3.98%(SD 0.67) respectively . The difference in HbA2 were significant (p value <0.0001).The difference in HbA2 levels between HbE trait and HbE disease was also significant (p value 0.036).Based on the HbF levels Sickle cell hemoglobinopathy was further classified. Conclusion:The difference in HbA2 levels in normal subjects, Thalassemia and hemoglobinopathies are statistically significant. The percentage of HbF in sickle cell gives information about coexisting hemoglobin disorder. In HbEhemoglobinopathy, HbA2 along with HbF identifies a specific group HbE/ β Thalassemia which often needs clinical intervention.

Utility of red blood cell parameters and indices of iron homeostasis in evaluation of microcytosis without anemia or with mild anemia: a diagnostic accuracy study

“…3 The gold standard for the diagnosis of βTT is HbA 2 estimation, with a cutoff value of greater than 3.8% in the range of 3.8 to 6.2%. 4 This can be detected by hemoglobin high-performance liquid chromatography (Hb-HPLC). 5 Differentiation of these main groups is necessitated by the point that iron treatment is not needed for thalassemia trait (TT).…”