Sickle cell anemia is diagnosed with a small set of blood tests, chiefly hemoglobin electrophoresis or HPLC, which detect abnormal hemoglobin S, and it is managed with a combination of prevention, disease-modifying medicines such as hydroxyurea, transfusion when needed, and in selected patients a curative transplant or gene therapy. The complexity comes from the fact that one faulty gene affects nearly every organ over a lifetime, so diagnosis is only the start of long-term, coordinated care.
Below I walk through what goes wrong in the red cell, which labs matter and how to read them, and how treatment is planned at different ages.
What Is Sickle Cell Anemia?
Sickle cell anemia is an inherited disorder in which a person receives a sickle gene from each parent. It is the most common and usually most severe form of sickle cell disease, a wider group that also includes combinations such as hemoglobin SC disease and sickle beta-thalassemia. It is most common in people with African, Middle Eastern, Indian and Mediterranean ancestry.
The Genetic Change
The cause is a single-letter change in the beta-globin gene on chromosome 11. Instead of normal adult hemoglobin (HbA), the body makes hemoglobin S (HbS). People who inherit one sickle gene have sickle cell trait; they are usually healthy but can pass the gene to their children. When both parents carry the trait, each pregnancy has a one-in-four chance of sickle cell anemia.
Why the Cells Sickle
When HbS gives up its oxygen, the molecules stick together into long, rigid fibers inside the erythrocytes. This bends the cell into the characteristic sickle shape. Sickled cells are stiff and sticky, so they block small blood vessels (vaso-occlusion) and break down early (hemolysis). A normal red cell lives about 120 days; a sickle cell survives only around 10 to 20 days.
How Sickle Cell Anemia Presents
Babies are protected for the first few months by fetal hemoglobin (HbF), so symptoms usually begin in infancy or early childhood. Presentation varies widely, even between siblings.
- Pain crises: sudden episodes of severe pain in bones, chest or abdomen, and painful swelling of the hands and feet (dactylitis) in young children.
- Chronic anemia: tiredness, pallor and jaundice from ongoing hemolysis.
- Infection: the spleen is damaged early (functional asplenia), which raises the risk of serious bacterial infection.
- Acute chest syndrome: chest pain, fever and new lung shadowing on X-ray, a medical emergency.
- Stroke: a particular risk in childhood.
- Splenic sequestration: sudden pooling of blood in the spleen in young children, causing a rapid fall in hemoglobin.
Care for children has its own priorities, which are covered in our guide to sickle cell anemia in pediatric patients.
Diagnostic Tests and Sickle Cell Anemia Labs
In many countries sickle cell anemia is now picked up by newborn screening, and confirmed with repeat testing. Older children and adults are diagnosed with the same tests. These sit alongside the routine anemia workup labs that measure severity.
| Test | What it shows | Typical finding in sickle cell anemia |
|---|---|---|
| Hemoglobin electrophoresis or HPLC | Types and proportions of hemoglobin | Mostly HbS, no HbA, variable HbF |
| Complete blood count (CBC) | Hemoglobin level and cell counts | Low hemoglobin, often raised white cell and platelet counts |
| Reticulocyte count | Young red cells released by the marrow | Raised, reflecting ongoing hemolysis |
| Blood film | Red cell shape under the microscope | Sickled cells, target cells, Howell-Jolly bodies |
| Bilirubin and LDH | Markers of red cell breakdown | Raised |
| DNA testing | The beta-globin gene itself | Two copies of the sickle mutation |
A sickle solubility test can show that HbS is present, but it cannot tell sickle cell trait from sickle cell anemia, so it is never used alone to make the diagnosis. Recent blood transfusion can also mask the true pattern, which is why the timing of testing matters.
Monitoring Tests
After diagnosis, regular checks look for organ damage before symptoms appear. Children typically have yearly transcranial Doppler ultrasound to assess stroke risk. Kidney function, urine protein, eye examinations and, in adults, heart and lung assessment are part of routine follow-up.
Treatment and Management Strategies
Management rests on three pillars: preventing complications, modifying the disease, and treating acute events quickly.
Prevention
Young children receive daily penicillin and a full vaccination schedule, including pneumococcal vaccines, to offset the loss of splenic function. Folic acid is often given, and families are taught to recognize fever and splenic enlargement early.
Disease-Modifying Treatment
- Hydroxyurea: raises fetal hemoglobin, which reduces sickling. It lowers the frequency of pain crises and acute chest syndrome and is now offered from infancy.
- Regular transfusion: used to prevent stroke in high-risk children and to manage some severe complications.
- L-glutamine and crizanlizumab: additional options in some countries for reducing pain crises. Voxelotor was withdrawn from the market in 2024.
Acute Care
Pain crises need prompt, adequate pain relief, fluids and assessment for complications. Fever in a person with sickle cell anemia is treated as an emergency because of infection risk.
Curative Options
Stem cell transplantation, ideally from a matched sibling, can cure the disease but carries significant risks. Gene therapies, which modify a patient’s own stem cells, are now approved in some countries for selected patients. With good care, the life span of sickle cell patients has improved considerably compared with previous generations.
When to See a Doctor
Seek urgent medical care for any of the following in someone with sickle cell anemia:
- Fever of 38.5°C (101.3°F) or higher
- Chest pain, cough or difficulty breathing
- Sudden weakness, facial drooping, confusion or difficulty speaking
- A rapidly enlarging spleen or unusual pallor in a child
- A painful erection lasting more than a few hours (priapism)
- Pain not controlled by the usual home plan
Frequently Asked Questions
Can a simple blood test tell if I have sickle cell anemia or just the trait?
Yes, hemoglobin electrophoresis or HPLC distinguishes them. People with the trait have both HbA and HbS, while those with sickle cell anemia have mostly HbS and no HbA. A solubility test alone cannot make this distinction.
Why is hydroxyurea offered to young children?
Hydroxyurea increases fetal hemoglobin, which protects red cells from sickling. Starting early reduces pain crises and hospital admissions. Blood counts are checked regularly to adjust the dose safely.
Is sickle cell anemia curable?
Stem cell transplantation and gene therapy can cure it, but both are intensive, carry real risks, and are suitable only for selected patients. For most people, lifelong management keeps the disease under control.
How often do I need check-ups?
Most people are reviewed in a specialist clinic at least once or twice a year, with more frequent visits for children, during pregnancy, or while on hydroxyurea or transfusion programs. Screening tests for the brain, kidneys, eyes and lungs are scheduled as part of this follow-up.
