The inherited blood disorder thalassemia can range in severity from mild to severe. Mild cases, usually caused by a single defect inherited from only one parent that affects one of the genes controlling the production of alpha or beta globulin, result in asymptomatic cases or in mild anemia. Moderate to severe cases occur when an individual inherits the disease from both parents, resulting in two or more defective genes and a clinical profile that can include severe anemia, jaundice, bone malformations and other problems.
Complete Blood Count Test (CBC)
The Lab Tests Online website explains that a complete blood count test looks at blood cell types, sizes and hemoglobin content. In a CBC test, the technician looks under the microscope to determine if there are fewer red blood cells than normal, whether hemoglobin is low in those blood cells and whether those cells are smaller than typical red blood cells. All of these are signs of thalassemia, and the determination that a patient has smaller than normal red blood cells is often the first sign of the disease.
Hemoglobinopathy (Hb) Test
For a hemoglobinopathy test, blood is drawn from the patient and investigated for unusually low levels of hemoglobin or abnormal ratios of the type of hemoglobin. Normal hemoglobin is mainly made up of hemoglobin A, but in patients with thalassemia, hemoglobin A2, F or H may be more prevalent.
Family Genetic Studies
Family genetic studies involve a detailed analysis of various family members to assess whether they have any of the various forms of thalassemia. Family members are asked for a detailed medical history, and blood tests are taken to find anyone who may be hidden carriers of the disease.
Prenatal Tests
For expectant parents who are carriers of thalassemia and have one gene that leaves them asymptomatic or with extremely mild symptoms, prenatal tests are available to determine whether the fetus has inherited the disorder. These include amniocentesis, which takes a sample of amniotic fluid for testing, and chronic villus sampling, which takes a portion of the placental tissue. These tests can not only give parents an idea of whether or not their child will inherit thalassemia, but also give indications as to the severity of the disease, according to the National Heart, Lung and Blood Institute.
DNA Tests
DNA tests are rarely done for thalassemia, according to the Lab Tests Online website, but they may be helpful in conjunction with family genetic studies. These tests look at the DNA of an individual to see if the person has one or more genes that contribute to the disorder.
