Sickling Screening Test – BC287
🧬 Hemoglobinopathy ScreenReport: Same Day
Sample Type: Blood (EDTA)
Test Code: BC287
The Sickling Screening Test is a rapid blood test used to detect the presence of abnormal Hemoglobin S (HbS). HbS is the type of hemoglobin that causes red blood cells to deform into a sickle or crescent shape under certain conditions, leading to Sickle Cell Disease or Sickle Cell Trait.
✔ A primary screening tool for identifying individuals with Sickle Hemoglobin (HbS).
✔ Helps detect both Sickle Cell Trait (carrier state) and Sickle Cell Disease.
✔ Important for premarital screening, newborn screening, and investigating certain types of anemia.
✔ A positive screening result requires confirmation with further tests like HPLC.
Detecting the Sickle Hemoglobin
Hemoglobin is the protein inside red blood cells responsible for carrying oxygen. Sickle Cell Disease is an inherited condition where a genetic mutation causes the body to produce an abnormal type of hemoglobin called Hemoglobin S (HbS). Under conditions of low oxygen, HbS molecules stick together and polymerize, forcing the normally flexible, disc-shaped red blood cells to become rigid and take on a characteristic sickle or crescent shape.
These misshapen cells can block blood flow in small vessels, causing pain (vaso-occlusive crises), organ damage, and severe anemia. The Sickling Screening Test is a simple, qualitative test that exploits this property. In the lab, a chemical is added to the blood sample that reduces the oxygen level. If HbS is present, the red blood cells will sickle, which can be observed under a microscope or by the turbidity (cloudiness) of the solution.
Trait vs. Disease: The Importance of Confirmation
This screening test is very effective at detecting the presence of HbS, but it cannot distinguish between:
- Sickle Cell Trait (HbAS): Where a person inherits one gene for HbS and one gene for normal hemoglobin (HbA). These individuals are generally healthy carriers but can pass the gene to their children.
- Sickle Cell Disease (HbSS): Where a person inherits two genes for HbS. This is the severe form of the illness.
- Other Hemoglobin Variants: Such as Hemoglobin SC disease.
Therefore, a positive sickling test is not a final diagnosis. It indicates the presence of HbS and must always be followed up with a more definitive test like Hemoglobin Electrophoresis or High-Performance Liquid Chromatography (HPLC) to determine the exact type and amount of abnormal hemoglobin present.
Frequently Asked Questions (FAQ)
Its purpose is to quickly screen for the presence of Hemoglobin S (HbS), the abnormal hemoglobin responsible for Sickle Cell Trait and Sickle Cell Disease.
Not necessarily. A positive result confirms you have Hemoglobin S, but it could mean you have either Sickle Cell Trait (usually asymptomatic carrier state) or Sickle Cell Disease. A follow-up test like HPLC is required to differentiate between the two.
A negative result means you do not have significant amounts of Hemoglobin S. However, it does not rule out other types of inherited hemoglobin disorders like Thalassemia or other variant hemoglobins.
This test is often used for newborn screening, premarital screening (especially in communities with a high prevalence of sickle cell), or for individuals with symptoms of unexplained anemia or pain crises.
No, fasting is not required for the Sickling Screening Test.