Alpha thalassemia can range from being asymptomatic to incompatible with ex utero life. To confirm diagnosis, get a good history, including ancestry, family history, and risk factors for iron deficiency, lead poisoning and other causes of microcytic anemia. Depending on pre-test probability, get a CBC to determine degree of microcytosis and anemia, +/- lead level, ferritin, etc. A Mentzer Index can help differentiate pure iron deficiency from pure thalassemia but it is difficult to confirm thalassemia if the patient is also iron deficient. A hemoglobin fractionation assay can diagnose HbH disease but does not reliably diagnose alpha thalassemia trait or silent carriers. HBA1 and HBA2 gene testing is usually required to confirm these mild forms. The newborn screen can hint at alpha thalassemia trait and diagnose HbH disease if those results are available.
If the patient is a child, he/she can be referred to pediatric hematology/oncology (PHO) to confirm diagnosis, provide education and genetic counseling to family, and/or help manage clinically-significant thalassemia. A brief family and personal history and a recent CBC are needed at time of PHO referral. Referrals missing this data will be delayed. Differentiation between iron deficiency and thalassemia and treatment of iron deficiency by the referring provider will make PHO consults most effective.
If the patient is an adult, medical hematologists can help diagnose microcytic anemia and manage HbH disease but do not have the bandwidth to counsel people who are silent carriers or have alpha thalassemia trait. Genetic counselors practicing in some primary care, hematology or obstetric clinics may provide this education as needed.
