Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
All U.S. newborns are screened for sickle cell disease.
Why it's done
- Family history of sickle cell or thalassemia
- Anemia with small red cells but normal iron
- Before or during pregnancy for carrier screening
Getting ready and what happens
- No special preparation is needed. A recent transfusion can affect results.
How the test is done
- A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.
What the results mean
Hemoglobin S
Some S with mostly normal A is sickle cell trait, which usually causes no problems. Mostly S is sickle cell disease.
Abnormal A2 or F levels
Can point to thalassemia trait or disease.
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related tests
Sources
Last updated 2026-11-13.