The only reliable way to know if you have sickle cell disease is a blood test, usually hemoglobin electrophoresis or HPLC, which shows which types of hemoglobin your red cells contain. Symptoms such as repeated pain episodes, anemia, and swelling of the hands and feet can raise suspicion, but they are not enough on their own. Most people with the disease are now identified at birth through newborn screening, and a single test can also tell you whether you carry the trait.
In my practice, I see adults who were never told their newborn screening result, teenagers wondering why they get pain crises, and couples planning a pregnancy who want to know their carrier status. This guide explains the clues, the tests, and what the results mean.
What Is Sickle Cell Disease?
Sickle cell disease (SCD) is an inherited blood disorder caused by an abnormal hemoglobin called hemoglobin S. When this hemoglobin gives up oxygen, it clumps into stiff strands that bend red cells into a crescent, or sickle, shape.
Sickled cells block small blood vessels and are destroyed quickly, lasting around 10 to 20 days instead of the normal 120. The result is ongoing anemia plus episodes of blocked blood flow that cause pain and organ damage. The condition is most common in people with ancestry from Africa, the Mediterranean, the Middle East, India, and parts of the Americas.
Signs That Could Point to Sickle Cell Disease
Symptoms usually begin from about five to six months of age, when protective fetal hemoglobin declines. Clues that should prompt testing include:
- Pain crises: sudden, severe pain in the bones, back, chest, or abdomen without an obvious injury.
- Dactylitis: painful, swollen hands or feet in an infant or toddler, often the earliest sign.
- Anemia: tiredness, pale skin, shortness of breath on exertion.
- Jaundice: yellow eyes or skin from rapid red cell breakdown.
- Frequent or severe infections, especially in young children.
- Delayed growth or puberty.
- Gallstones at a young age, or vision problems from retinal changes.
None of these is specific. Many other conditions cause anemia or joint pain, and some people with milder forms, such as HbSC, may have few symptoms for years. That is why testing, not guessing, gives the answer.
Who Should Get Tested?
Sickle cell disease is caused by a change in the HBB gene, which makes the beta chain of hemoglobin. Sickle cell disease is caused by a child inheriting an abnormal copy from each parent, while one copy gives sickle cell trait, a usually symptom-free carrier state.
Testing makes sense if you:
- Have symptoms like those above
- Have a parent, sibling, or child with sickle cell disease or trait
- Were born where newborn screening was unavailable or your result is unknown
- Are planning a pregnancy, or are pregnant, and your ancestry places you in a higher-risk group
- Have unexplained anemia or an abnormal blood count
If both parents carry the trait, each pregnancy has a 1 in 4 chance of a child with the disease, a 1 in 2 chance of a carrier, and a 1 in 4 chance of neither.
Tests That Confirm Sickle Cell Disease
A diagnosis rests on laboratory results. Here is what each test shows.
| Test | What it shows | When it is used |
|---|---|---|
| Newborn screening | Presence of hemoglobin S and other variants | Routinely at birth in many countries |
| Hemoglobin electrophoresis or HPLC | Types and amounts of hemoglobin (HbA, HbS, HbC, HbF) | The main confirmatory test at any age |
| Complete blood count (CBC) | Hemoglobin level, red cell indices, white cells, platelets | Assesses anemia and helps separate from thalassemia |
| Reticulocyte count | How fast the marrow is making new red cells | High when cells are being destroyed early |
| Blood film | Sickled cells and target cells under the microscope | Supports the diagnosis |
| DNA testing | The exact HBB gene changes | Unclear results, prenatal diagnosis |
A quick “sickle solubility” test only shows whether hemoglobin S is present. It cannot tell trait from disease, so it should never be the final word.
Understanding Your Results
The report lists which hemoglobins are present. Roughly speaking:
- Mostly HbA, no HbS: no sickle gene.
- HbA greater than HbS: sickle cell trait (HbAS). You are a carrier.
- HbS with no HbA, plus HbF: consistent with HbSS or HbS beta-zero thalassemia.
- HbS and HbC in similar amounts: HbSC disease.
- HbS greater than HbA: suggests HbS beta-plus thalassemia.
A recent blood transfusion can temporarily mask the true pattern, so tell the lab if you have had one. Interpretation is best done by a hematologist, who may also test other family members.
What Happens After a Diagnosis
A confirmed diagnosis opens the door to care that prevents complications. For children, that includes daily penicillin, usually until age five, a full vaccine schedule, and transcranial Doppler screening for stroke risk from age two. Hydroxyurea, which raises fetal hemoglobin and reduces pain crises, is offered to most people with HbSS.
Blood transfusions, a written pain plan, good hydration, and avoiding temperature extremes all help. For some patients, stem cell transplant or newer gene therapies can offer a cure. If you learn you have the trait, genetic counseling can explain what it means for future children.
When to See a Doctor
Book an appointment for testing if any of the risk factors or symptoms above apply to you. Seek urgent care if you or your child has:
- A fever of 38.5°C (101.3°F) or higher in someone known or suspected to have SCD
- Chest pain or difficulty breathing
- Sudden weakness, trouble speaking, or a severe headache
- Severe pain that does not settle with simple measures
- Marked paleness, a swollen belly, or unusual drowsiness in a child
Frequently Asked Questions
Can you have sickle cell disease and not know it?
It is possible, especially with milder types such as HbSC or HbS beta-plus thalassemia, or if you were born without newborn screening. Sickle cell trait very often goes unrecognized because it rarely causes symptoms.
Can a standard blood count diagnose sickle cell?
No. A CBC can show anemia or unusual red cells, but it cannot identify hemoglobin S. You need hemoglobin electrophoresis, HPLC, or DNA testing.
How do I find out my newborn screening result?
Ask your pediatrician or family doctor, who may be able to request records from the screening program. If records are unavailable, a new hemoglobin test gives the same information.
Can sickle cell disease develop later in life?
No. It is present from birth because it is inherited. What can change is when symptoms become noticeable or when the diagnosis is finally made.
