Diagnosis of Beta Thalassemia

**123**

**Chapter 8**

**Abstract**

**1. Introduction**

*Thanusak Tatu*

Laboratory Diagnosis of

β-Thalassemia and HbE, each, is a syndrome resulted from quantitative and qualitative defects of β-globin chain, respectively. In addition to history retrieve and physical examination, diagnosis of these disorders requires laboratory information. Laboratory tests that are conventionally performed to diagnose the β-thalassemia and HbE are classified into two groups, based on the purposes, including the screening tests and confirmatory tests. The screening tests are aimed to screen for carriers of the β-thalassemia and HbE, while confirmatory tests are the tests performed to definitely diagnose these disorders. This chapter will explain all of these tests, the information of which will be useful for those who are working and interested in the β-thalassemia and HbE.

Thalassemia is a type of anemia caused by reduction or absence of globin chain synthesis, which results in imbalanced-globin chain synthesis; the major pathogenesis of the disease. The unaffected globin chains continuing to be synthesized at the normal synthetic rate tend to form homotetramers and aggregation that can harm the red blood cells both at young and mature stages. The α-globin chain aggregation formed in β-thalassemia causes ineffective erythropoiesis due to oxidative stress. The γ- and β-globin chain homotetramer (γ4, β4) formed in α-thalassemia harm mature erythrocytes. The γ4 or Hb Bart's has very high oxygen affinity and inhibits oxygen release from erythrocytes which, in turn, results in tissue anoxia. The β4 or HbH is an unstable hemoglobin and precipitates easily under the stress condition in the body. Once precipitates, the erythrocytes are removed by the RE system resulting in anemia. Severe thalassemia cases suffer from chronic and marked anemia with life relying solely on blood transfusion. Anemia causes expansion of bone marrow, leading to osteoporosis and changes of bone structure. Blood transfusion and hemolysis cause iron overloading state in the body which causes several complications such as

**Keywords:** β-thalassemia, HbE, screening tests, confirmatory tests,

heart disease, growth retardation, diabetes mellitus, and infection.

have the highest prevalence of the disease [1].

Thalassemia is considered the most common autosomal single-gene disorder worldwide. It can be found in more than 150 countries with an estimated carrier frequency of about 7%. The Mediterranean region, certain parts of North and West Africa, Middle East, Indian subcontinent, Southern Far East, and South East Asia

thalassemia carrier, HbE carrier, β-thalassemia disease

**1.1 Thalassemia and hemoglobinopathies**

β-Thalassemia and HbE

## **Chapter 8**
