Sickle cell trait is a blood condition that gets passed down through some families in their genes. It can’t turn into sickle cell disease and it doesn’t usually cause health problems.
A person has sickle cell trait when they inherit a copy of the “sickle cell gene” from one of their parents. With only 1 copy of the sickle cell gene, they don’t have sickle cell disease, but they can pass a copy of the gene on.A person with sickle cell trait is also called a “carrier.”
Sickle cell trait doesn’t usually cause health problems. Symptoms are rare and usually can be prevented.
Sickle cell disease is a blood disorder where red blood cells are curved instead of round. The curved cells can get stuck in and block small blood vessels. Blood can't flow normally, which can lead to pain and organ damage. People with sickle cell disease need lifelong medical care.
To understand how someone gets sickle cell trait, it helps to know about the beta-globin gene.
Everybody has 2 copies of the beta-globin gene that they inherit, one from each parent. Beta-globin genes tell the body how to make hemoglobin (HEE-muh-glow-bin), a protein in red blood cells that carries oxygen. One type of beta-globin gene that someone can inherit is called the sickle beta-globin gene, or “sickle cell gene” for short.
A person gets sickle cell trait by inheriting a normal beta-globin gene from one parent and a sickle beta-globin gene (sickle cell gene) from the other parent.
A genetic counselor can explain how sickle cell trait, sickle cell disease, and other blood disorders can run in families.
Most people with sickle cell trait don’t have the problems that can happen with sickle cell disease. That's because their normal copy of the beta-globin gene lets their bodies make enough normal hemoglobin.
Rarely, though, a person with sickle cell trait may have:
A person with sickle cell trait who has any of these symptoms should talk to their doctor.
To diagnose sickle cell trait, doctors use a blood test called hemoglobin electrophoresis (eh-lek-truh-fer-EE-sis).
In the United States, every newborn baby gets this test as part of newborn screening. Many other countries routinely test newborns too. A newborn screening can tell if a baby has sickle cell trait, sickle cell disease, or another problem with their hemoglobin.
People who don’t know their status can ask their doctor for a hemoglobin electrophoresis test. Sometimes, pregnant women who don’t know if they have sickle cell trait will get the test. This lets them know their baby's chances of having a hemoglobin problem.
If your child has sickle cell trait:
You can learn more about sickle cell trait online at:
Reviewed by: Corinna L. Schultz, MD
Date Reviewed: Nov 1, 2022