Sickle Cell Screen
Sickle Cell Screen, A sickle cell screen refers to a medical test or screening process used to detect the presence of sickle cell disease or sickle cell trait. Sickle cell disease is a genetic disorder characterized by abnormal hemoglobin, the protein in red blood cells that carries oxygen. The abnormal hemoglobin causes red blood cells to become rigid and shaped like sickles, leading to various complications such as pain, anemia, and organ damage.
- Newborn Screening: In many countries, newborns are routinely screened for sickle cell disease shortly after birth. This involves collecting a small blood sample, usually obtained from a heel prick, and testing it for the presence of abnormal hemoglobin.
- Hemoglobin Electrophoresis: This laboratory test separates different types of hemoglobin based on their electrical charge. It can identify the presence of abnormal hemoglobin associated with sickle cell disease or sickle cell trait.
- Sickle Solubility Test: This is a simple and rapid test that looks for the insolubility of sickle hemoglobin under certain conditions. It’s often used as a preliminary screening tool.
- Genetic Testing: Molecular genetic testing can identify specific mutations in the HBB gene, which codes for the beta-globin subunit of hemoglobin. This type of testing can provide detailed information about the specific genetic changes associated with sickle cell disease or sickle cell trait.
- Hemoglobin S (HbS) Testing: This test specifically measures the presence of hemoglobin S, the abnormal hemoglobin associated with sickle cell disease.
It’s important to note that individuals with sickle cell trait typically do not experience the same severe symptoms as those with sickle cell disease. However, carriers of the trait can pass it on to their children. Testing and awareness are crucial for genetic counseling and family planning.
- Pain Crises (Vaso-Occlusive Crises): One of the hallmark symptoms of sickle cell disease is pain episodes or crises. These occur when sickle-shaped red blood cells block blood flow through small blood vessels, leading to pain in various parts of the body, particularly in the chest, abdomen, joints, and bones.
- Anemia: Sickle cells are fragile and can break apart easily, leading to a shortage of red blood cells (anemia). Anemia can cause fatigue, weakness, and shortness of breath.
- Swelling of Hands and Feet: Sickle cell disease can cause the hands and feet to swell, a condition known as dactylitis. This is often one of the first signs of the disease in infants.
- Infections: People with sickle cell disease are more susceptible to infections, as the abnormal shape of the red blood cells can impair the function of the immune system.
- Delayed Growth: In children with sickle cell disease, the condition can affect growth and development.
- Vision Problems: Sickle cells can block blood vessels in the eye, leading to vision problems and even permanent damage to the retina.
- Organ Damage: Over time, repeated episodes of blockage and decreased blood flow can lead to damage to organs, including the spleen, kidneys, and liver.
- Stroke: Sickle cell disease increases the risk of stroke, especially in children. Blood vessels in the brain can be blocked by sickle cells, leading to a lack of oxygen and a stroke.
- Jaundice: The breakdown of red blood cells can result in the release of bilirubin, causing yellowing of the skin and eyes (jaundice).
What does the test result mean?
- Normal Hemoglobin (AA): This means the person does not have sickle cell disease or sickle cell trait. Both copies of the hemoglobin gene are normal.
- Sickle Cell Trait (AS): This means the person is a carrier of the sickle cell gene. They have one normal hemoglobin gene (A) and one sickle cell hemoglobin gene (S). Individuals with sickle cell trait usually do not experience the symptoms of sickle cell disease, but they can pass the sickle cell gene to their children.
- Sickle Cell Disease (SS or Sβ0): This indicates that both copies of the hemoglobin gene are the sickle cell type. People with sickle cell disease have a higher risk of complications related to the abnormal shape of their red blood cells, including pain crises, anemia, and organ damage.
It’s important to note that there are different types of sickle cell disease, and the specific genetic mutations can vary. The test results are usually interpreted by healthcare professionals who consider the individual’s genetic makeup and any symptoms they may be experiencing.