From the Guidelines
Thalassemia diagnosis should be made through a combination of blood tests, including a complete blood count (CBC), hemoglobin electrophoresis, and genetic testing, as these tests can identify abnormal hemoglobin patterns and specific gene mutations or deletions affecting the alpha or beta globin chains 1.
Diagnosis Approach
The initial screening typically begins with a CBC, which often shows microcytic, hypochromic anemia in thalassemia patients.
- Hemoglobin electrophoresis is then used to identify abnormal hemoglobin patterns characteristic of different thalassemia types.
- For alpha thalassemia, genetic testing is particularly important as electrophoresis may not always show clear abnormalities.
- DNA analysis can identify specific gene mutations or deletions affecting the alpha or beta globin chains.
Additional Tests and Considerations
Family history assessment is also valuable, especially in high-risk ethnic populations such as those of Mediterranean, African, Middle Eastern, or Southeast Asian descent.
- Additional tests may include iron studies to differentiate thalassemia from iron deficiency anemia, as both conditions present with similar red blood cell characteristics.
- Early diagnosis is crucial, particularly for severe forms like beta thalassemia major, which requires lifelong management including regular blood transfusions and iron chelation therapy to prevent complications from iron overload, as highlighted in the American Heart Association consensus statement 1.
Prenatal Diagnosis
Prenatal diagnosis is also available for couples with known thalassemia traits who wish to assess the risk in pregnancy.
- This approach allows for early identification and management of the condition, improving outcomes for affected individuals.
- The use of cardiac T2* magnetic resonance for estimating cardiac iron and assessing cardiac function is also an important aspect of managing thalassemia major, as it helps in identifying cardiac iron overload and guiding treatment decisions 1.
From the Research
Thalassemia Diagnosis Methods
- Thalassemia diagnosis can be achieved through various methods, including complete blood count, hemoglobin analysis, and molecular studies to identify mutations of globin genes 2
- Third-generation sequencing (TGS) has been shown to be effective in identifying Thal gene mutations, with a higher detection rate compared to PCR-based methods 3
- TGS can detect rare thalassemia gene mutations, including HBA1/2 and HBB gene mutations, and can confirm the cis/trans configuration of 2 allelic gene mutations in one step 3
Clinical Classification and Screening
- Thalassemia diseases are classified into transfusion-dependent thalassemia and non-transfusion-dependent thalassemia, based on the clinical severity of patients 2
- Screening for thalassemia involves blood routine tests and hemoglobin electrophoresis, combined with TGS, to minimize the risk of missed or incorrect diagnoses 3
- Carrier screening, genetic counseling, and prenatal diagnosis are important for prevention of thalassemia 4
Molecular Diagnosis
- Molecular genetic testing plays a crucial role in identifying individuals carrying thalassemia traits that can cause adverse outcomes in offspring 5
- Molecular diagnosis can detect deletional forms of β-thalassemia and α-thalassemia, which may be masked in the presence of β-thalassemia 5
- Next-generation sequencing can be used to identify β-thalassemic mutations and their effects on γ-globin levels 6