Sickle Cell Testing

Sickle cell testing is used to screen for the presence of sickle cell trait or to confirm the presence of sickle cell disease. Some people are more likely than others to have sickle cell trait or disease. Testing is recommended for these people. Because of the severity of the disease, people who are most likely to have the sickle cell trait and who are planning to have children may wish to seek genetic counseling. Prenatal screening also is available.

ExitCare ImageWhen a person is affected with sickle cell trait or disease, their red blood cells can take the shape of sickles rather than a normal round shape. This allows the cells to get stuck in vessels and cause problems.


A blood sample is obtained by inserting a needle into a vein in the arm. The sample is tested for the presence of hemoglobin S (HbS), which causes sickle cell trait or disease. In sickle cell disease, one abnormal gene is inherited from each of the parents.

The test can fail to detect hemoglobin S under the following circumstances:

  • You have had a blood transfusion within 3 to 4 months before the sickle cell test.

  • You have the red blood cell disease that increases red blood cell production (polycythemia).

  • Tests that are done in infants younger than 3 months.

  • You were taking certain drugs, such as phenothiazines, when the test was done.


Negative for Hemoglobin S (HbS).

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.