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Hemoglobin Electrophoresis

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.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

The health professional drawing blood will:

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Attach a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure on the site and then put on a bandage.

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Risks

There is very little chance of a problem from having a blood sample taken from a vein.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
  • Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

A hemoglobin electrophoresis test is a blood test done to check the different types of hemoglobin in the blood. Results are ready in several days.

Normal

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Hemoglobin electrophoresis1

Hemoglobin A1:

96.5%–98.5% of total hemoglobin or 0.96–0.985 mass fraction

Hemoglobin A2:

1.5%–3.5% of total hemoglobin or 0.015–0.035 mass fraction

Hemoglobin F:

0%–1% of total hemoglobin or 0–0.01 mass fraction

Abnormal hemoglobin types:

None

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.1

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Having a blood transfusion in the past 3 months.
  • Having iron deficiency anemia. This can cause falsely low results for hemoglobin A2.

What To Think About

If you are planning to have children and are found to have abnormal types of hemoglobin in your blood, you might consider genetic counseling. This can help you and your partner see how likely you are to have children with certain inherited forms of anemia (such as sickle cell disease or thalassemia).

References

Citations

  1. Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

Credits

By Healthwise Staff
E. Gregory Thompson, MD - Internal Medicine
Joseph O'Donnell, MD - Hematology, Oncology
Last Revised May 29, 2012

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