Couples who are considering having children may want to undergo genetic testing to find out if they are carriers of thalassemias or other disorders that can be passed on to children. Because people with thalassemia trait do not experience symptoms, it is possible for the trait to go undiagnosed in families, even over generations.

A complete blood count (CBC) test includes a measure of the size of a patient’s red blood cells. This is known as mean corpuscular volume (MVC). Patients with an MVC of less than 75 may be genetic carriers for thalassemia. This reading may be lower in children.

If CBC testing indicates the presence of the thalassemia gene, follow-up testing such as hemoglobin electrophoresis will be performed to confirm the finding. Confirmation testing for alpha thalassemia can be more complicated. A special DNA test called alpha globin DNA mutation analysis may be necessary. This test is only available at only a few medical centers in the United States. A patient’s physician can take a blood sample and send it to one of these centers for analysis.