Sickle cell disease is a genetic blood disorder characterized by abnormally shaped red blood cells. These cells, resembling a crescent or “sickle,” can block blood flow, leading to pain, organ damage, and other serious health problems. Early testing and detection are important for managing the condition and improving health outcomes.
Who Should Get Tested
Newborn screening is a common way to identify sickle cell disease or trait early in life. All newborns in the United States are screened for sickle cell disease, typically through a heel prick blood sample collected within 24 to 48 hours after birth, and sometimes again at seven to fourteen days of age. This early detection allows for prompt initiation of care, such as prophylactic antibiotics to prevent life-threatening infections.
Testing is also recommended for individuals with a family history of sickle cell disease or sickle cell trait. Pregnant individuals also undergo prenatal screening. Knowing your family’s history can inform your decision to get tested.
People considering starting a family, particularly those from ethnic groups with a higher prevalence of sickle cell disease, may also consider testing. These groups include individuals of African, Mediterranean, South Asian, Hispanic, and Caribbean descent. For instance, sickle cell disease affects approximately 1 in every 365 Black or African American births and about 1 in every 16,300 Hispanic American births.
The Testing Process
Testing for sickle cell disease typically involves a simple blood test. For newborns, a few drops of blood are collected from a heel prick onto a special card. For older children and adults, a blood sample is usually drawn from a vein in the arm, a quick process.
Once collected, the blood sample is sent to a laboratory for analysis. Various tests can be performed to detect the presence of hemoglobin S, the abnormal protein characteristic of sickle cells. Common methods include hemoglobin electrophoresis, high-performance liquid chromatography (HPLC), and isoelectric focusing, which are considered reliable for defining an individual’s hemoglobin type. Genetic testing, which looks for the sickle cell gene itself, can also be used to confirm a diagnosis, especially if blood test results are unclear.
HPLC is effective immediately after birth. Testing can typically be done at a doctor’s office, hospital, or specialized clinics.
Understanding Your Results
After a sickle cell test, results will indicate whether an individual has normal hemoglobin, sickle cell trait, or sickle cell disease. A negative result means no sickle cell disease or trait is present.
A positive test result may indicate either sickle cell trait or sickle cell disease. If the initial screening test is positive, a confirmatory test like hemoglobin electrophoresis is often performed to distinguish between these two conditions. Individuals with sickle cell trait carry one copy of the sickle cell gene and usually do not experience symptoms, but they can pass the trait on to their children.
Having sickle cell disease means an individual has inherited two copies of the sickle cell gene. In such cases, genetic counseling is often recommended to help individuals and families understand the implications of the results, especially concerning family planning. Counselors can explain the inheritance pattern and the risks for future children, providing support and information about the condition.