Most people in the United States find out they have sickle cell disease as newborns, through a routine blood test done in the hospital within days of birth. Every state screens for it. But if you weren’t screened, were born outside the U.S., or are wondering whether your symptoms point to sickle cell, a simple blood test from your doctor can confirm or rule it out at any age.
Newborn Screening Catches Most Cases
Sickle cell disease is on the Recommended Uniform Screening Panel, a federal list of conditions that every newborn in the U.S. should be tested for. The test uses a few drops of blood from a baby’s heel, typically collected 24 to 48 hours after birth. Results go to your pediatrician, who notifies parents if the screen is positive. This means most Americans born in a hospital already know their status, even if they don’t remember being told.
If you were born in another country, born at home without follow-up testing, or your records were lost, you may genuinely not know. In that case, the same type of blood test can be done as an adult.
Symptoms That Show Up First
Sickle cell disease is genetic, meaning you’re born with it. But symptoms rarely appear before 5 or 6 months of age, because newborns still carry a type of hemoglobin from fetal development that temporarily protects their red blood cells. Once that fades, the sickle-shaped cells start causing problems.
The earliest signs in infants include:
- Yellowing of the skin or eyes (jaundice): This happens when abnormal red blood cells break apart faster than the body can replace them.
- Unusual fussiness or fatigue: Babies with sickle cell often seem extremely tired because their blood can’t carry enough oxygen.
- Swollen hands and feet: Called dactylitis, this painful swelling occurs when sickle-shaped cells block small blood vessels. It can appear as early as age 1.
In older children and adults, the hallmark symptom is episodes of intense pain, often called pain crises. These happen when sickle cells clump together and block blood flow, most commonly in the chest, abdomen, joints, and bones. Episodes can last hours to days and vary widely in frequency. Some people have a few per year, others have them monthly.
Signs in Adults Who Haven’t Been Diagnosed
Undiagnosed adults with sickle cell disease typically have a history of unexplained health problems that, in hindsight, form a pattern. Chronic anemia is the most consistent finding: you may feel persistently tired, short of breath during mild activity, or lightheaded. Your skin or the whites of your eyes may have a yellowish tint.
Other clues include recurring episodes of severe bone or joint pain without an obvious injury, frequent infections (especially pneumonia), vision changes from damaged blood vessels in the eye, and delayed growth during childhood. Some adults develop kidney problems, leg ulcers that heal slowly, or episodes of sudden chest pain with fever and difficulty breathing, a serious complication called acute chest syndrome.
None of these symptoms alone proves sickle cell disease. Many overlap with other conditions. But if you have several of them, especially alongside a family history or African, Mediterranean, Middle Eastern, or South Asian ancestry, testing is straightforward.
Who Is Most Likely to Have It
Sickle cell disease affects about 100,000 people in the United States. More than 90% are Black or African American, and an estimated 3% to 9% are Hispanic or Latino. It occurs in roughly 1 out of every 365 Black or African American births and about 1 out of every 16,300 Hispanic American births.
The disease requires inheriting a sickle cell gene from both parents. If you inherit it from only one parent, you have sickle cell trait, which is far more common. About 1 in 13 Black or African American babies is born with the trait. Most people with sickle cell trait live completely normal lives and never have symptoms, though in rare cases, extreme physical exertion, high altitude, dehydration, or temperature extremes can trigger complications like kidney or spleen damage.
The Blood Test That Confirms It
The definitive test is a hemoglobin analysis, which separates and measures the different types of hemoglobin in your blood. In a healthy person, the vast majority of hemoglobin is the normal “A” type. In someone with sickle cell disease, roughly 80% or more is the abnormal “S” type, with no normal hemoglobin A present at all. People with sickle cell trait, by contrast, have both types.
Your doctor orders this as a standard blood draw. The lab uses one of two main methods: an older technique called electrophoresis, which separates hemoglobin types by electrical charge, or a newer automated method that’s faster and more precise, especially for detecting small quantities of unusual hemoglobin variants. Many labs now use the automated approach as a first-line screen. In some cases, a second confirmatory method is needed because certain hemoglobin combinations can look similar on initial testing.
A complete blood count is usually run alongside the hemoglobin analysis. It shows whether you’re anemic and gives clues about the size and shape of your red blood cells, which helps distinguish sickle cell disease from related conditions like thalassemia. In sickle cell anemia, red blood cells are typically normal-sized but misshapen, while in thalassemia they tend to be smaller than normal.
Sickle Cell Trait vs. Sickle Cell Disease
This distinction matters enormously. Having sickle cell trait (one copy of the gene) is not the same as having sickle cell disease (two copies). Trait carriers produce enough normal hemoglobin that their red blood cells function well under ordinary conditions. They don’t have chronic anemia, pain crises, or organ damage.
Knowing your trait status is still important, mainly for family planning. If both parents carry the trait, each pregnancy has a 25% chance of producing a child with sickle cell disease. A simple blood test can tell you whether you’re a carrier, and genetic counselors can walk you through what the results mean for your family.
Testing Before Birth
If both parents carry a sickle cell gene, prenatal testing can determine whether the baby will have the disease. This can be done as early as 8 to 10 weeks into pregnancy using a small sample from the placenta, or later using amniotic fluid. These tests look directly for the sickle cell gene in the baby’s DNA rather than measuring hemoglobin, since the baby’s blood chemistry is still developing.
Getting Tested as an Adult
If you suspect you have sickle cell disease or want to know your trait status, start with your primary care doctor. They can order the hemoglobin analysis and complete blood count. If results are positive or complex, you’ll typically be referred to a hematologist, a specialist in blood disorders, who manages ongoing care.
For people diagnosed as adults, the initial workup usually includes additional tests to check for organ damage that may have accumulated over the years, particularly in the kidneys, spleen, eyes, and lungs. Early diagnosis, even if it comes late, opens the door to treatments that reduce pain crises and prevent complications.