Sickle Cell Trait

Understand sickle cell trait.
Learn about testing. Know if you’re a carrier.

Worldwide, more than 100 million people have sickle cell trait. And many people carry the trait without knowing. It’s important to understand the facts about sickle cell trait, so you can know what to expect for yourself and your family.

What is SCT? How do you get it?

Sickle cell trait is a blood disorder that runs in families. In some cases, the red blood cells may form the shape of a sickle or crescent moon, but for most people the blood cells will be normal and round. Typically, people with SCT don’t experience any health issues because of the trait — but it can happen.

To have the trait, it means that one of your parents passed it down to you at birth. You inherit the trait from only one parent, which is a key difference between SCT and sickle cell disease (SCD).


Sickle Cell Trait VS Sickle Cell Disease

Sickle cell trait is not a disease, even though it can bring health problems. 

SCT and SCD are closely related, but they aren’t the same. With SCT, you have inherited one sickle cell gene from one parent, and a “normal” gene from the other. To have sickle cell disease, this means you’ve inherited two sickle cell genes, one from each parent. (In some types of sickle cell disease, you’ve inherited one sickle cell gene and a different type of “abnormal hemoglobin” from each parent.) Having a second sickle cell gene (or abnormal hemoglobin) makes all the difference.

Health Problems And Complications

Generally, people with sickle cell trait are able to lead normal, healthy and happy lives. Most people don’t experience the pain crises and other issues more commonly associated with sickle cell disease. However, there are specific health problems to watch out for, even though they’re not common.

In particular, people with SCT:

  • May be more likely to have urinary tract infections (UTIs)
  • Might see blood in their urine (or pee)
  • May have pain crises


It’s recommended that people with SCT avoid dehydration, low oxygen levels and high altitudes – as this could be dangerous or even fatal. Athletes and people that are very active especially need to take measures to take care of their health. It’s rare, but extreme physical activity and severe dehydration can lead to heat stroke and sudden death.

To take charge of your health, take time to understand if you’re a carrier of SCT.

Are You A Carrier Of SCT?

Learn about testing.

Knowing your trait status is key, for you and your family. A simple blood test is all it takes.

If you do have the trait, you’ll then know what health issues to look out for and can take steps to keep yourself well. You’ll also know your chances of passing SCT on to future children, as well as their likelihood of developing sickle cell disease.

In some US states, you may be able to receive free SCT testing. Please check with your local clinic or hospital to see what’s available. You can also check online for services near you. In the US today, most newborns are automatically screened for SCT. Check your children’s health records to verify this information.

Learn More About Sickle Cell Trait from These Great Resources:


“Although I work at a hospital I wasn’t really aware of what it [sickle cell trait] was. I was not really into it, as far as information wise, it was an older time. There was not a lot of information out there. We went into genetic counseling once I got with my partner now and we found out that he had the trait, so yeah.”

- Caira, an adult carrier of SCT

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