Sickle cell disease (SCD) is a group of inherited disorders where red blood cells deform into a characteristic sickle shape due to a change in hemoglobin, the protein carrying oxygen. Inheriting one altered gene from a parent results in sickle cell trait (SCT), meaning the person is a carrier. Inheriting two altered genes results in SCD. While SCT is usually asymptomatic, SCD can lead to serious health complications like pain crises and organ damage. Testing is the first step in understanding one’s status for personal health management or family planning.
Who Should Be Tested for Sickle Cell
Testing for sickle cell begins with universal newborn screening, which is mandated in all U.S. states and territories. Infants are tested shortly after birth, typically via a heel-stick sample. This early detection allows for starting preventative treatment for SCD, such as penicillin prophylaxis, before symptoms emerge.
Screening is also advised for individuals with a known family history of SCD or SCT. Genetic counseling and testing are important for prospective parents to understand the risks of passing the gene to their children. If both parents have the sickle cell trait, their child has a 25% chance of inheriting sickle cell disease.
Testing is recommended for individuals whose ancestry places them at a higher statistical risk for the condition. This includes people of African, Mediterranean, Middle Eastern, South Asian, and Hispanic descent. For example, about 1 in 13 African American newborns inherit the trait, making targeted testing a proactive health measure for adults in these communities.
Methods Used for Sickle Cell Testing
The initial method for infants is the newborn screening, which uses a dried blood spot collected from a heel prick. This sample is analyzed in a laboratory to identify the specific types of hemoglobin present.
For older children and adults, the standard diagnostic test involves a venous blood draw performed in a clinic or lab. The blood sample is then subjected to specific laboratory techniques to separate and identify different hemoglobin variants.
The most common techniques are Hemoglobin Electrophoresis, High-Performance Liquid Chromatography (HPLC), and Isoelectric Focusing (IEF). These methods separate hemoglobin based on its properties, allowing for the accurate identification and quantification of hemoglobin S (HbS), the abnormal form associated with sickle cell. DNA analysis, or genetic testing, identifies the specific mutation in the beta-globin gene and is often used to clarify complex or unclear initial results.
Prenatal testing options are available for couples planning a family to determine the status of a developing fetus. These tests typically involve analyzing a sample of amniotic fluid or tissue from the placenta, known as chorionic villus sampling (CVS). This genetic analysis provides information early in the pregnancy regarding the presence of the sickle cell gene.
Locating Testing Facilities and Resources
The first and most accessible place to begin testing is with a Primary Care Provider (PCP) or Pediatrician. Your doctor can order the necessary blood test and provide a referral to a laboratory, which is often required for insurance coverage.
For individuals without insurance or seeking low-cost options, Community Health Centers (CHCs) and Federally Qualified Health Centers (FQHCs) are excellent resources. These centers offer services on a sliding scale based on income, making testing more financially accessible. State Public Health Departments often run screening programs or can direct you to local resources.
Specialized Sickle Cell Treatment Centers and regional Hemoglobinopathy Labs are available for more complex cases or follow-up testing. These centers have expert staff, including hematologists and genetic counselors, who can provide comprehensive guidance. Additionally, some national lab chains offer direct-to-consumer testing, allowing individuals to order and pay for a blood draw at a patient service center.
Before proceeding, confirm insurance coverage with your provider, as policies vary regarding genetic screening. If paying out-of-pocket, non-profit organizations, such as the Sickle Cell Disease Association of America, may offer free or reduced-cost testing and financial assistance programs. Confirming the final price with the laboratory and your insurance company helps prevent unexpected medical costs.
Understanding Your Test Results
Once the laboratory analysis is complete, the results indicate the type of hemoglobin present. A result showing only normal hemoglobin (HbA) means the individual does not have the sickle cell gene.
A result showing both hemoglobin A and hemoglobin S (HbAS) indicates Sickle Cell Trait (SCT). Individuals with SCT are carriers with one copy of the gene and are generally healthy, but they can pass the gene to their children.
A result indicating the presence of two abnormal genes, such as HbSS, confirms a diagnosis of Sickle Cell Disease (SCD). This means the person has the condition and requires ongoing medical management.
Receiving a positive result for either SCT or SCD necessitates follow-up with a healthcare professional. Those diagnosed with SCD require a referral to a hematologist to begin a structured care plan. Individuals identified as carriers (SCT) are encouraged to seek genetic counseling to explain inheritance patterns, discuss family planning, and interpret the risk to future children.