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Beta thalassemia is a hereditary hematological disorder with defects in beta globin chain synthesis. Based on the underlying molecular defect, they can have variable phenotypes ranging from asymptomatic carriers to severe transfusion-dependent anemia. The laboratory evaluation is based on various hematological tests like complete blood count, iron studies, peripheral smear, hemoglobin analysis, and molecular testing. The most reliable method for diagnosis is hemoglobin analysis, for which various techniques like high-performance liquid chromatography (HPLC), electrophoresis, and chromatography are available. Molecular diagnoses are needed in cases of severe transfusion-dependent and mild-moderate non-transfusion-dependent cases. DNA evaluation by chorionic villi sampling or culture of the fetal cell is used for a prenatal diagnosis. As it is a recessive disease, recognizing carriers can help prevent severe disease. Objectives: Explain the common laboratory findings of beta thalassemia. Summarize each diagnostic test used in beta thalassemia. Outline the testing procedure for beta thalassemia. Review the pathophysiology of beta thalassemia. Access free multiple choice questions on this topic.

Beta thalassemia is a group of inherited hemoglobinopathies that can lead to anemia of varying severity.[1] Beta thalassemias are caused by a number of mutations that affect the different aspects of beta globin production, like the transcription, translation, or stability of the beta-globin product. This eventually leads to defective hemoglobin, which is susceptible to destruction.[2] The diagnosis starts at the clinic, where apparent signs and symptoms can be gathered based on history and examination. The age and ethnic background of the patient are valuable clinical information. To confirm the diagnosis, laboratory testing is a necessary requisite. Laboratory evaluation for beta thalassemia can vary from routine blood tests like peripheral smears, complete blood count, iron studies, and hemoglobin analysis to more complex tests, including genetic testing.[3]

The genetic mutation results in a deficiency of the beta-globin chain. The excess unpaired alpha globin leads to hemolysis of Red blood cells in the bone marrow and extramedullary hematopoiesis, causing chronic anemia.[5] As the body tries to compensate, it leads to extramedullary hematopoiesis, which can manifest as skeletal abnormalities in the face and the long bones, hepatosplenomegaly, growth impairment, and kidney enlargement.[7] The constellation of symptoms, complications, and the degree of anemia may make the patient transfusion-dependent, which can have various complications. Beta thalassemia patients have high iron levels in their Red blood cell membrane due to denatured hemoglobin.[5] Ineffective erythropoiesis, chronic anemia, and hypoxia can cause increased GI absorption of iron.[8] This, in combination with iron from the destruction of RBCs and repeated transfusions, causes iron deposition in tissues leading to hemosiderosis.[9] Free iron species like the labile plasma iron and the labile iron pool in RBCs can contribute if transferrin saturation exceeds 70%. These free iron species eventually generate reactive oxygen species, which cause tissue damage and organ dysfunction.[7]

It is of paramount importance that the clinician understands a detailed workup of a suspected beta thalassemia patient. Every step in diagnosis requires communication, coordination, and responsibility by the staff involved, whether it is storage, processing, or reporting. Regular updates about diagnostic criteria and laboratory techniques must be performed. All the staff members must be aware of the safety precautions required in the lab.