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Hemoglobin (Fetal)

Does this test have other names?

Hemoglobin analysis, hemoglobin electrophoresis

What is this test?

A fetal hemoglobin test is a blood test that checks the amount of fetal hemoglobin (Hb F) in the blood. Fetal hemoglobin is one of many types of hemoglobin. It is present in high levels in fetuses, but usually drops to trace amounts about six months after birth. If HbF is at higher than normal levels, it can mean you have thalassemia, myeloid leukemia, or sickle cell anemia.

Why do I need this test?

You may need this test if your doctor suspects that you have a blood disorder related to a high level of fetal hemoglobin in your blood. People with most of these disorders don't have symptoms but may have varying degrees of anemia. Symptoms related to anemia can include fatigue, pain, irregular heartbeat, and other heart problems.

The disorders are genetic, so your doctor may also recommend this test if you have a family history of the disease.  

What other tests might I have along with this test?

A variety of tests are used to diagnose blood disorders related to fetal hemoglobin. You may also have a blood smear, iron studies, or DNA analysis.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

In healthy adults, Hb F is typically present only in trace amounts. If this amount is higher, you may have a blood disorder such as thalassemia, sickle cell anemia, or another condition related to high levels of fetal hemoglobin. 

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. 

What might affect my test results?

If you are an adult or child who has higher than normal levels of fetal hemoglobin, you may have anemia, leukemia, or a sickle cell disorder. But, the fetal hemoglobin test alone does not tell  which condition you might have. Some people with higher than normal levels of fetal hemoglobin don't have any symptoms. Further testing is needed to find out the specific nature of your blood disorder.

How do I get ready for this test?

You don't need to prepare for this test.  Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.