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. See a picture of hemoglobin .

The most common types of normal hemoglobin are:

• 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 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 A2. This is a normal type of hemoglobin found in small amounts in adults.

More than 400 different types of abnormal hemoglobin have been found, but 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 a sickle cell disorder.
• Hemoglobin H (heavy hemoglobin). This type of hemoglobin may be present in certain types of thalassemia.

Hemoglobin S and hemoglobin C are the most common types of abnormal hemoglobins 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.

Why It Is Done

Hemoglobin electrophoresis is done to:

• Find each type of hemoglobin in the blood. This can be used to diagnose certain types of anemia (such as thalassemia).
• Check treatment for diseases that have abnormal types of hemoglobin in the blood.
• Help couples find out how likely they are to have a child with certain forms of anemia that can be passed from a parent to a child (inherited).

How To Prepare

Tell your doctor if you are getting iron therapy for iron deficiency anemia.