Test Overview

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.^{footnote 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.

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.

How It Is Done

A health professional uses a needle to take a blood sample, usually from the arm.

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

Results are ready in several days.

Normal

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

High and low values

• Higher-than-normal amounts of both hemoglobin A2 and hemoglobin F may mean a mild form of thalassemia is present. A very low level of hemoglobin A and a high level of hemoglobin F may mean a more severe form of thalassemia. High levels of hemoglobin F may be seen in a rare condition called hereditary persistence of fetal hemoglobin.
• Hemoglobin S in moderate amounts can mean that sickle cell trait is present. Hemoglobin S in high amounts means sickle cell disease.
• Hemoglobin C in low amounts can mean that hemoglobin C trait is present. Hemoglobin C in high amounts means hemoglobin C disease, which causes anemia and an enlarged spleen.
• Hemoglobin types S and C mean hemoglobin S-C disease, which causes a mild or moderate form of sickle cell disease.
• Hemoglobin E in low amounts means the presence of hemoglobin E trait. Hemoglobin E in high amounts means hemoglobin E disease, which causes anemia and smaller-than-normal red blood cells.
• Hemoglobin types other than S, C, D, and E are rare. But over 350 types of abnormal hemoglobin have been found.^{footnote 1}