Sickle Cell Test

Hemoglobin S Test

Test Overview

A sickle cell test is a blood test done to screen for sickle cell trait or sickle cell disease. Sickle cell disease is an inherited blood disease that causes red blood cells to be deformed (sickle-shaped). The red blood cells deform because they contain an abnormal type of hemoglobin, called hemoglobin S, instead of the normal hemoglobin, called hemoglobin A.

Sickled blood cells are destroyed by the body faster than normal blood cells, which can lead to the body receiving an inadequate supply of oxygen; this condition is called sickle cell anemia. Also, sickled blood cells can become trapped in blood vessels reducing or blocking blood flow. This can damage organs, muscles, and bones and may lead to life-threatening conditions.

The best way to screen for sickle cell trait or sickle cell disease is to examine the blood using a method called high-performance liquid chromatography (HPLC). This test identifies which type of hemoglobin is present. To confirm the results of HPLC, a genetic information (DNA) test may be done.

Sickle cell disease is an autosomal recessive disease. This means that to have the disease, a person must inherit a gene for the disease from both parents. Each person inherits two chromosomes (one from each parent). As a result, a person may have:

• Two chromosomes that produce normal hemoglobin (hemoglobin A). These people have normal red blood cells, unless they have some other disease.
• One chromosome that produces hemoglobin A and one that produces hemoglobin S. These people carry the sickle cell trait (and are called "a carrier"), but they do not have sickle cell disease. Sickle cell trait is usually a harmless condition.
• Two chromosomes that produce hemoglobin S. These people have sickle cell anemia. Both parents either carry the sickle cell trait or have the disease. Sickled red blood cells often cause recurring health problems called sickle cell crises.
• One chromosome that produces hemoglobin S and one that produces some other abnormal type of hemoglobin. Depending on the other type of abnormal hemoglobin, these people may have mild or severe sickle cell disorder.

	Go to top of page	Go to next section
Author:	Jan Nissl, RN, BS	Last Updated: March 12, 2007
Medical Review:	Adam Husney, MD - Family Medicine Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine Martin Steinberg, MD - Hematology
© 1995-2008 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.This information does not replace the advice of a doctor. Healthwise disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.