From the Guidelines
Thalassemia screening should primarily involve a complete blood count (CBC) with red blood cell indices, followed by hemoglobin electrophoresis or high-performance liquid chromatography (HPLC) to identify abnormal hemoglobin patterns. When considering the management of patients with thalassemia, it's essential to note that those who received blood transfusions before 1992 should be tested for anti-HCV antibodies, as recommended by an international panel 1. However, for the purpose of screening for thalassemia itself, the focus should be on tests that directly assess hemoglobin production and red blood cell characteristics. Some key points to consider in thalassemia screening include:
- Initial screening with a CBC to identify microcytic anemia
- Hemoglobin electrophoresis or HPLC to detect abnormal hemoglobin patterns
- DNA analysis for definitive diagnosis of specific genetic mutations
- Serum ferritin tests to rule out iron deficiency
- Peripheral blood smear examination to observe red blood cell morphology
- Prenatal screening via chorionic villus sampling or amniocentesis with DNA analysis for at-risk pregnancies
- Screening of family members of affected individuals to identify carriers or affected relatives. While the study by 1 focuses on the management of chronic viral hepatitis in patients with thalassemia, the primary approach to screening for thalassemia itself involves direct assessment of hemoglobin and red blood cell characteristics, rather than tests for viral infections.
From the Research
Tests to Screen for Thalassemia
- Hemoglobin electrophoresis may reveal common characteristics of different thalassemia subtypes, but genetic testing is required to confirm the diagnosis 2
- Molecular genetic testing serves an important role in identifying individuals carrying thalassemia traits that can cause adverse outcomes in offspring 3
- Molecular screening can be performed by Gap-PCR, ARMS-PCR, Sanger sequencing, and MLPA to detect alpha- and beta-thalassemia alleles 4
- Techniques such as multiplex gap-polymerase chain reaction, single-tube multiplex polymerase chain reaction, multiplex ligation-dependent probe amplification, and loop-mediated isothermal amplification can be used to detect common deletion of alpha-thalassemia 5
- Capillary electrophoresis system can be used to diagnose various types of hemoglobinopathies, including thalassemias, by separating and quantifying the common hemoglobin fractions 6
Laboratory Diagnosis
- Complete blood count, blood smear, and hemoglobin quantification by high performance liquid chromatography and capillary electrophoresis may not possibly detect all the thalassemia diseases 5
- Sanger sequencing is widely used to detect non-deletion mutations of alpha-thalassemia 5
- Next-generation sequencing can be used to detect both deletion and point mutations of alpha-thalassemia 5