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Sickle cell test

The sickle cell test looks for the abnormal hemoglobin in the blood that causes the disease sickle cell anemia.

How the Test is Performed

A blood sample is needed.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a bruise. This soon goes away.

Why the Test is Performed

This test is done to tell if a person has abnormal hemoglobin that causes sickle cell disease and sickle cell trait. Hemoglobin is a protein in red blood cells that carries oxygen.

In sickle cell disease, a person has two abnormal hemoglobin S genes. A person with sickle cell trait has only one of these abnormal genes and no symptoms, or only mild ones.

This test does not tell the difference between these two conditions. Another test, called hemoglobin electrophoresis, will be done.

Normal Results

A negative test result is normal.  

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results. 

What Abnormal Results Mean

  • Sickle cell anemia
  • Sickle cell trait

Iron deficiency or blood transfusions within the past 3 months can cause a false negative result.

Risks

Veins and arteries vary in size from one patient to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight, but may include:

  • Excessive bleeding
  • Fainting or feeling light-headed
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)

Alternative Names

Sickledex; Hgb S test

References

Steinberg MH. Sickle cell disease and associated hemoglobinopathies. In: Goldman L, Schafer AI, eds.Goldman's Cecil Medicine

Vajpayee N, Graham SS, Bern S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds.Henry's Clinical Diagnosis and Management by Laboratory Methods

Update Date 2/24/2014

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