Test Overview

A hemoglobin electrophoresis test is a blood test done to evaluate the different types of hemoglobin in the bloodstream. Hemoglobin is the substance in red blood cells that carries oxygen. See an illustration of hemoglobin .

The most common types of normal hemoglobin include:

• 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 produced after birth. Some diseases, such as sickle cell anemia, aplastic anemia, and leukemia, are associated with abnormal types of hemoglobin and increased amounts of hemoglobin F. In some of these diseases, treatment may include actually increasing the amount of hemoglobin F.
• Hemoglobin A. This is the major type of hemoglobin found normally in adults. Some diseases, such as severe forms of thalassemia, may cause hemoglobin A levels to decrease and hemoglobin F levels to increase.
• 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 identified, but the most common include:

• Hemoglobin S. This type of hemoglobin is present in sickle cell anemia.
• Hemoglobin C. This is another type of hemoglobin found in sickle cell anemia.
• Hemoglobin E. This type of hemoglobin is found in people of Southeast Asian descent.
• Hemoglobin D. This type of hemoglobin may be present with sickle cell anemia or thalassemia.
• 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 identified by an electrophoresis test.

Electrophoresis uses an electrical current to separate normal and abnormal types of hemoglobin in the blood because they have different electrical charges and move at different rates in the electrical current. The amount of each hemoglobin type is then measured.

Finding an abnormal amount of normal hemoglobin or an abnormal type of hemoglobin in the blood may indicate that a disease is present. Abnormal hemoglobin types may be present without any other findings, produce mild diseases that do not cause any symptoms, or cause diseases that can be life-threatening. For example, hemoglobin S is found in sickle cell anemia, which is a serious abnormality of the blood.

Medical review	Author	Last updated
Renée M. Crichlow, MD - Family Medicine	Jan Nissl, RN, BS	October 28, 2004

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