What is a hemoglobin electrophoresis test?

A hemoglobin electrophoresis test is a blood test used to measure and identify the different types of hemoglobin in your bloodstream. Hemoglobin is the protein inside red blood cells responsible for transporting oxygen to your tissues and organs.

Genetic mutations can cause your body to produce hemoglobin that is formed incorrectly. This abnormal hemoglobin can cause too little oxygen to reach your tissues and organs.

There are hundreds of different types of hemoglobin. They include:

  • Hemoglobin F: This is also known as fetal hemoglobin. It’s the type found in growing fetuses and newborns. It’s replaced with hemoglobin A soon after birth.
  • Hemoglobin A: This is also known as adult hemoglobin. It’s the most common type of hemoglobin. It’s found in healthy children and adults.
  • Hemoglobin C, D, E, M, and S: These are rare types of abnormal hemoglobin caused by genetic mutations.

A hemoglobin electrophoresis test doesn’t tell you about the amount of hemoglobin in your blood — that’s done in a complete blood count. The levels that a hemoglobin electrophoresis test refer to are the percentages of the different types of hemoglobin that may be found in your blood. This is different in babies and adults:

In infants

Hemoglobin is mostly made up of hemoglobin F in fetuses. Hemoglobin F still makes up the majority of hemoglobin in newborns. It quickly declines by the time your baby is a year old:

AgeHemoglobin F percentage
newborn60 to 80%
1+ year1 to 2%

In adults

The normal levels of the types of hemoglobin in adults are:

Type of hemoglobinPercentage
hemoglobin A95% to 98%
hemoglobin A22% to 3%
hemoglobin F1% to 2%
hemoglobin S0%
hemoglobin C0%

You acquire different abnormal types of hemoglobin by inheriting gene mutations on the genes that are responsible for producing hemoglobin. Your doctor may recommend a hemoglobin electrophoresis test to determine if you have a disorder that causes the production of abnormal hemoglobin. Reasons your doctor may want you to do a hemoglobin electrophoresis test include:

1. As part of a routine checkup: Your doctor may have your hemoglobin tested to follow up on a complete blood test during a routine physical.

2. To diagnose blood disorders: Your doctor may have you do a hemoglobin electrophoresis test if you’re showing symptoms of anemia. The test will help them find any abnormal types of hemoglobin in your blood. These could be a sign of disorders including:

3. To monitor treatment: If you’re being treated for a condition that causes abnormal types of hemoglobin, your doctor will monitor your levels of the different types of hemoglobin with a hemoglobin electrophoresis.

4. To screen for genetic conditions: People who have a family history of inherited anemias such as thalassemia or sickle cell anemia may choose to screen for these genetic disorders before having children. A hemoglobin electrophoresis will indicate if there are any abnormal types of hemoglobin caused by genetic disorders. Newborns are also routinely screened for these genetic hemoglobin disorders. Your doctor may also want to test your child if you have a family history of abnormal hemoglobin or they have anemia that’s not caused by an iron deficiency.

You don’t need to do anything special to prepare for a hemoglobin electrophoresis.

You usually need to go to a lab to have your blood drawn. At the lab, the healthcare provider takes a sample of blood from your arm or hand: They first clean the site with a swab of rubbing alcohol. Then they insert a small needle with a tube attached to collect blood. When enough blood has been drawn, they remove the needle and cover the site with a gauze pad. They then send your blood sample to a laboratory for analysis.

In the laboratory, a process called electrophoresis passes an electrical current through the hemoglobin in your blood sample. This causes the different types of hemoglobin to separate into different bands. Your blood sample is then compared to a healthy sample to determine which types of hemoglobin are present.

As with any blood test, there are minimal risks. These include:

  • bruising
  • bleeding
  • infection at the puncture site

In rare cases, the vein may swell after blood is drawn. This condition, known as phlebitis, can be treated with a warm compress several times a day. Ongoing bleeding could be a problem if you have a bleeding disorder or are taking blood-thinning medication, such as warfarin (Coumadin) or aspirin (Bufferin).

If your results show abnormal hemoglobin levels, they may be caused by:

  • hemoglobin C disease, a genetic disorder that leads to severe anemia
  • rare hemoglobinopathy, a group of genetic disorders causing the abnormal production or structure of red blood cells
  • sickle cell anemia
  • thalassemia

Your doctor will do follow-up tests if a hemoglobin electrophoresis tests shows that you have abnormal types of hemoglobin.