Flow Cytometry Confirmation Post Newborn Screening for SCID in England

Area of Science:

• Immunology
• Newborn Screening
• Flow Cytometry

Background:

• Severe Combined Immunodeficiency (SCID) screening in England began in September 2021.
• TREC analysis is the initial screening method.
• Flow cytometry is the confirmatory diagnostic test for infants with low TREC levels.

Purpose of the Study:

• To describe the flow cytometry approach for diagnosing SCID and T lymphopenias in England.
• To outline the established protocols and reference values used by immunology laboratories.
• To discuss the ongoing need for monitoring and potential adjustments to diagnostic criteria.

Main Methods:

• Utilizing flow cytometry to analyze T cell populations.
• Establishing specific protocols and reference values for SCID, T lymphopenia, and healthy infants.
• Implementing TREC analysis as the primary screening tool.

Main Results:

• Flow cytometry protocols are in place to diagnose SCID and T lymphopenias.
• Reference values have been established to differentiate between affected infants and healthy babies.
• The current approach allows for the identification of infants requiring further investigation after low TREC screening.

Conclusions:

• The flow cytometry method in England provides a defined approach to diagnose SCID and T lymphopenias post-TREC screening.
• Continuous monitoring of flow cytometry values is essential for maintaining diagnostic accuracy over time.
• Standardized protocols ensure consistent identification of infants with T cell deficiencies.