BETA THALASSEMIA SCREENING

Testing for thalassemia trait involves having a single blood sample drawn. This can be done during a doctor's appointment, genetic counseling session, or sometimes through community health fairs offering this service. The following screening tests identify most types of thalassemia trait, as well as sickle cell trait, E trait, and most other known hemoglobin traits: Hemoglobin electrophoresis with quantitative hemoglobin A2 and hemoglobin F Complete blood count Iron studies (free erythrocyte protoporphyrin, ferritin, and/or other iron studies) Individuals with beta thalassemia trait usually have evidence of microcytosis and increased levels of hemoglobin A2. Hemoglobin F is sometimes elevated as well. Individuals with alpha thalassemia trait usually have evidence of microcytosis and normal levels of hemoglobin A2 and F. Sometimes trait status cannot be determined by these screening tests alone. Results may be ambiguous for a variety of reasons. If iron deficiency is detected, an individual must be retested after completing iron supplement therapy. Occasionally, DNA testing that directly examines the alpha and/or beta globin genes is necessary. DNA testing is the only way to determine silent alpha thalassemia trait and the related hemoglobin trait called hemoglobin Constant Spring. DNA testing may also be necessary in order to allow for the option of prenatal testing. It is important for individuals to be aware of their thalassemia trait status, particularly individuals of reproductive age. Depending on the hemoglobin type of a current or future partner, future children may be at risk for thalassemia disease or other related hemoglobin diseases. Prenatal and other testing options are available to couples found to be at risk for having a baby with disease. If you have learned that you have thalassemia trait, you may have questions about how this will affect you and other family members. Your doctor may be able to answer these questions or refer you to a genetic counselor in your area. You can also locate a genetic counselor through the website of the National Society of Genetic Counselors, www.nsgc.org. Informing other family members of the possibility that they may also have thalassemia trait can be difficult and time consuming. We've created some letters that can be easily printed out and distributed to family members. These letters describe inheritance, testing, and the significance of thalassemia trait and disease. There is also a fact sheet available for download with information about hemoglobin E trait, which is related to the thalassemia traits.