Hemoglobinopathy Evaluation Test-Why am I having this test?

Hemoglobinopathy evaluation test is a blood test to check for certain blood disorders that are passed down through families (hemoglobinopathies). You may need this test if you:

• Are at risk because of your ethnic background or family history.
• Want to know if you may pass a gene for a blood disorder onto your child.
• Have unexplained symptoms such as weakness, fatigue, yellow skin or eyes (jaundice), or pale skin, and your health care provider suspects a hemoglobinopathy.
• Have abnormal results on a complete blood test (CBC) or a blood test that looks at blood cells under a microscope (peripheral smear).

This test is also included in newborn screening tests that are done to look for hemoglobin disorders in newborns.

What is being tested?

Hemoglobin (Hgb) is a type of protein in the blood that carries oxygen. This test measures the amount of normal Hgb in your blood and checks for abnormal forms of Hgb (variants).

Normal Hgb includes:

• Hgb A1.
• Hgb A2.
• Hgb F.

Common Hgb variants are:

• Hgb S.
• Hgb C.
• Hgb E.

Less common variants are:

• Hgb F.
• Hgb H.
• Hgb Barts.
• Hgb D.
• Hgb G.
• Hgb J.
• Hgb M.
• Hgb Constant Spring.
• Mixed variants.

The hemoglobinopathy evaluation test may involve several methods to check a blood sample for hemoglobin abnormalities and variants. These may include:

• A hemoglobin solubility test to check for hemoglobin S.
• Hemoglobin electrophoresis.
• Hemoglobin isoelectric focusing.
• High performance liquid chromatography.
• Capillary zone electrophoresis.
• Mass spectrometry.

The method used varies by lab and depends on the type of hemoglobinopathy that you are being tested for.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel. In newborns, a blood sample may be collected with a heel stick.

Tell a health care provider about:

• Any blood transfusions you may have had in the past few months.
• Any allergies you have.
• All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any surgeries you have had.
• Any blood disorders you have.
• Whether you are pregnant or may be pregnant.

How are the results reported?

Your test results will report the amounts of normal and abnormal Hgb by percentage.

What do the results mean?

Normal Hgb results include:

• Hgb A1: 95–98%.
• Hgb A2: 2–3%.
• Hgb F: 2% or less.

A hemoglobin evaluation test may show abnormal forms, combinations, or elevations in the percentage of certain types of Hgb that are associated with certain medical conditions. These may include:

• Sickle cell disease. Majority increase in Hgb S, no Hgb A1, and increased Hgb F.
• Sickle cell trait. Slight decrease in Hgb A1 and about 40% increase in Hgb S.
• Hemoglobin C disease. Majority increase in Hgb C and no Hgb A1.
• Beta thalassemia major. Majority increase in Hgb F and little or no Hgb A1.
• Beta thalassemia minor. Majority increase in Hgb A1, 4–8% increase in Hgb A2, and slightly increased Hgb F.
• Hemoglobin H disease (also called alpha thalassemia). Majority increase in Hgb A1 and slight increase in Hgb H.
• Hemoglobin E disease. Majority increase in Hgb E.

To diagnose a hemoglobinopathy, your test results will be considered along with other tests including CBC, blood smear, reticulocyte count (the number of immature red blood cells), iron levels, and genetic testing.

Your health care provider may refer you to a hematology specialist to discuss what your individual results mean.

Questions to ask your health care provider:

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What other tests do I need?
• What are my treatment options?
• What are my next steps?

Summary

• A hemoglobinopathy evaluation test is a blood test to check for certain blood disorders that are passed down through families (hemoglobinopathies).
• Hemoglobin (Hgb) is a type of protein in the blood that carries oxygen. This test measures the amount of normal Hgb in your blood and checks for abnormal forms of Hgb (variants).
• You may need this test if you are at risk of a hemoglobinopathy or if you have unexplained symptoms and your health care provider suspects a hemoglobinopathy.