A hemoglobin electrophoresis test is a blood test done to check the different types of hemoglobin in the blood. Hemoglobin is the substance in red blood cells that carries oxygen.
The most common types of normal hemoglobin are:
Hemoglobin A. This is the most common type of hemoglobin found normally in adults. Some diseases, such as severe forms of thalassemia, may cause hemoglobin A levels to be low and hemoglobin F levels to be high.
Hemoglobin F (fetal hemoglobin). This type is normally found in fetuses and newborn babies. Hemoglobin F is replaced by hemoglobin A (adult hemoglobin) shortly after birth; only very small amounts of hemoglobin F are made after birth. Some diseases, such as sickle cell disease, aplastic anemia, and leukemia, have abnormal types of hemoglobin and higher amounts of hemoglobin F.
Hemoglobin A2. This is a normal type of hemoglobin found in small amounts in adults.
There are more than 350 types of abnormal hemoglobin.1 The most common are:
Hemoglobin S. This type of hemoglobin is present in sickle cell disease.
Hemoglobin C. This type of hemoglobin does not carry oxygen well.
Hemoglobin E. This type of hemoglobin is found in people of Southeast Asian descent.
Hemoglobin D. This type of hemoglobin is present in some sickle cell disorders.
Hemoglobin S and hemoglobin C are the most common types of abnormal hemoglobin that may be found by an electrophoresis test.
Electrophoresis uses an electrical current to separate normal and abnormal types of hemoglobin in the blood. Hemoglobin types have different electrical charges and move at different speeds. The amount of each hemoglobin type in the current is measured.
An abnormal amount of normal hemoglobin or an abnormal type of hemoglobin in the blood may mean that a disease is present. Abnormal hemoglobin types may be present without any other symptoms, may cause mild diseases that do not have symptoms, or cause diseases that can be life-threatening. For example, hemoglobin S is found in sickle cell disease, which is a serious abnormality of the blood and causes serious problems.