What is a hemoglobin electrophoresis test?
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.
If levels of HgbA or HgbF are too high or too low, it can indicate certain types of anemia.
Abnormal types of hemoglobin include:
- Hemoglobin (Hgb) S. This type of hemoglobin is found in sickle cell disease. Sickle cell disease is an inherited disorder that causes the body to make stiff, sickle-shaped red blood cells. Healthy red blood cells are flexible so they can move easily through blood vessels. Sickle cells can get stuck in the blood vessels, causing severe and chronic pain, infections, and other complications.
- Hemoglobin (Hgb) C. This type of hemoglobin does not carry oxygen well. It can cause a mild form of anemia.
- Hemoglobin (Hgb) E. This type of hemoglobin is mostly found in people of Southeast Asian descent. People with HgbE usually have no symptoms or mild symptoms of anemia.
A hemoglobin electrophoresis test applies an electric current to a blood sample. This separates normal and abnormal types of hemoglobin. Each type of hemoglobin can then be measured individually.
Other names: Hb electrophoresis, hemoglobin evaluation, hemoglobinopathy evaluation, hemoglobin fractionation, Hb ELP, sickle cell screen.
What’s the difference between a hemoglobin test and hemoglobin electrophoresis?
A hemoglobin test measures the amount of hemoglobin in your red blood cells. Hemoglobin electrophoresis analyzes the different types of hemoglobin in your red blood cells.
What are the different hemoglobin types?
Healthcare providers typically test for the four common hemoglobin types:
- Hemoglobin Types A11 and A2 (HgbA1 and A2): Hemoglobin A11 accounts for most of the hemoglobin in your normal red blood cells. Hemoglobin A2 accounts for about 2% to 3 % of your total hemoglobin.
- Hemoglobin Type F (HgbF): Normally, this hemoglobin type accounts for the largest part of red blood cells in fetuses, babies and children up to age 3. A high type F hemoglobin level in adults is considered an abnormal hemoglobin level.
- Hemoglobin Type S (HgbS): This hemoglobin type is a symptom of sickle cell anemia. Sickle cell anemia is an example of sickle cell disease. Sickle cell anemia is a serious illness that most commonly affects people who are Black.
- Hemoglobin C (HgbC): This hemoglobin type is linked to hemolytic anemia that develops when your red blood cells are destroyed more easily than normal red blood cells or have a shorter life span than normal red blood cells. Like sickle cell anemia, hemoglobin C most commonly affects people who are Black.
Normal levels of hemoglobin types
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:
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:
|Age||Hemoglobin F percentage|
|newborn||60 to 80%|
|1+ year||1 to 2%|
The normal levels of the types of hemoglobin in adults are:
|Type of hemoglobin||Percentage|
|hemoglobin A||95% to 98%|
|hemoglobin A2||2% to 3%|
|hemoglobin F||1% to 2%|
What is it used for?
Hemoglobin electrophoresis measures hemoglobin levels and looks for abnormal types of hemoglobin. It’s most often used to help diagnose anemia, sickle cell disease, and other hemoglobin disorders.
Why do I need hemoglobin electrophoresis?
You may need testing if you have symptoms of a hemoglobin disorder. These include:
- Pale skin
- Jaundice, a condition that causes your skin and eyes to turn yellow
- Severe pain (sickle cell disease)
- Growth problems (in children)
If you’ve just had a baby, your newborn will be tested as part of a newborn screening. Newborn screening is a group of tests given to most American babies shortly after birth. The screening checks for a variety of conditions. Many of these conditions can be treated if found early.
You may also want testing if you are at risk for having a child with sickle cell disease or another inherited hemoglobin disorder. Risk factors include:
- Family history
- Ethnic background
- In the United States, most people with sickle cell disease are of African ancestry.
- Thalassemia, another inherited hemoglobin disorder, is most common among people of Italian, Greek, Middle Eastern, Southern Asian, and African descent.
What happens during hemoglobin electrophoresis?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
To test a newborn, a health care provider will clean your baby’s heel with alcohol and poke the heel with a small needle. The provider will collect a few drops of blood and put a bandage on the site.
What is the difference between isoelectric focusing and electrophoresis?
Isoelectric focusing (IEF) is another technique for identifying abnormal hemoglobin. IEF and electrophoresis both use electric currents to separate hemoglobin types.
Where and how a hemoglobin electrophoresis test is administered
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.
The risks of a hemoglobin electrophoresis
As with any blood test, there are minimal risks. These include:
- 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).
What to expect after the test
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
Your doctor will do follow-up tests if a hemoglobin electrophoresis tests shows that you have abnormal types of hemoglobin.
What causes high hemoglobin levels?
High hemoglobin levels generally accompany high red blood cell counts. Remember, hemoglobin is found in red blood cells, so the higher your red blood cell count, the higher your hemoglobin level and vice versa.
A high red blood cell count and hemoglobin level can indicate several things, including:
- Congenital heart disease. This condition can make it hard for your heart to effectively pump blood and deliver oxygen throughout your body. In response, your body sometimes produces additional red blood cells.
- Dehydration. Not having enough fluid can cause red blood cell counts to appear higher because there isn’t as much fluid to balance them.
- Kidney tumors. Some kidney tumors stimulate your kidneys to make excess erythropoietin, a hormone that stimulates red blood cell production.
- Lung disease. If your lungs aren’t working effectively, your body may try to produce more red blood cells to help carry oxygen.
- Polycythemia vera. This condition causes your body to produce extra red blood cells.
What are low hemoglobin levels?
A low hemoglobin level is usually seen with low red blood cell counts.
Some medical conditions that can cause this include:
- Bone marrow disorders. These conditions, such as leukemia, lymphoma, or aplastic anemia, can all cause low red blood cell counts.
- Kidney failure. When your kidneys aren’t functioning properly, they don’t produce enough of the hormone erythropoietin that stimulates red blood cell production.
- Uterine fibroids. These are tumors that usually aren’t cancerous, but they can cause significant bleeding, leading to lower red blood cell counts.
- Conditions that destroy red blood cells. These include sickle cell anemia, thalassemia, G6PD deficiency, and hereditary spherocytosis.
You may also be more likely to have low hemoglobin levels if you:
- have a condition that causes chronic bleeding, such as gastric ulcers, colon polyps, or heavy menstrual periods
- have a folate, iron, or vitamin B-12 deficiency
- are pregnant
- were involved in a traumatic accident, such as a car accident
- have a family history of disorders that affect red blood cell counts, such as altered oxygen sensing
- live at a high altitude
- recently received a blood transfusion
Learn how to raise your hemoglobin.
What about hemoglobin A1c?
When having blood work done, you might also see results for hemoglobin A1c (HbA1c), sometimes called glycated hemoglobin. An HbA1c test measures the amount of glycated hemoglobin, which is hemoglobin that has glucose attached to it, in your blood.
Doctors often order this test for people with diabetes. It helps to give a clearer picture of someone’s average blood glucose levels over the course of 2 to 4 months. Glucose, also called blood sugar, circulates throughout your blood and attaches to hemoglobin.
The more glucose in your blood, the more likely you are to have higher levels of glycated hemoglobin. The glucose stays attached to the hemoglobin for about 120 days. A high HbA1c level indicates that someone’s blood sugar has been high for several months.
In most cases, someone with diabetes should aim for an HbA1c level of 7 percent or less. Those without diabetes tend to have HbA1c levels of about 5.7 percent. If you have diabetes and a high HbA1c level, you may need to adjust your medication.
What do the results mean?
Your results will show the types of hemoglobin found and the levels of each.
Hemoglobin levels that are too high or too low may mean:
- Thalassemia, a condition that affects the production of hemoglobin. Symptoms range from mild to severe.
- Sickle cell trait. In this condition, you have one sickle cell gene and one normal gene. Most people with sickle cell trait do not have health problems.
- Sickle cell disease
- Hemoglobin C disease, a condition that causes a mild form of anemia and sometimes an enlarged spleen and joint pain
- Hemoglobin S-C disease, a condition that causes a mild or moderate form of sickle cell disease
Your results may also show whether a specific disorder is mild, moderate, or severe.
There are several options for treating thalassemia and other hemoglobin disorders. Until recently, treatment options for sickle cell disease were limited. But now, promising new therapies have become available. If you or your child was diagnosed with a sickle cell disease or other hemoglobin disorder, talk to your provider about treatment options.
Is there anything else I need to know about hemoglobin electrophoresis?
If you are at risk of having a child with an inherited hemoglobin disorder, you may want to speak to a genetic counselor. A genetic counselor is a specially trained professional in genetics and genetic testing. He or she can help you understand the disorder and your risk of passing it along to your child.