Elevated IRT levels in African-American infants: implications for newborn screening in an ethnically diverse...

Area of Science:

• Medical screening
• Pediatrics
• Genetics

Background:

• Newborn screening (NBS) for Cystic Fibrosis (CF) is crucial for early detection and intervention.
• Elevated Immunoreactive Trypsinogen (IRT) levels are a primary indicator in CF NBS.
• Disparities in screening results among different ethnic groups warrant investigation.

Purpose of the Study:

• To analyze the implications of elevated IRT levels in African-American infants within New York's CF NBS program.
• To assess the positive predictive value (PPV) of IRT screening in this population.
• To identify strategies for improving screening accuracy and reducing false positives.

Main Methods:

• Retrospective analysis of NBS data over four years in New York.
• Comparison of IRT levels between African-American infants and the general infant population.
• Evaluation of CF mutation status in screen-positive infants.

Main Results:

• African-American infants exhibited a statistically significant twofold greater relative risk for IRT levels above the 95th percentile.
• The PPV for a screen-positive result in African-American infants was low, at 0.3%.
• A majority of screen-positive African-American infants were in the top 0.2% IRT group but lacked CF mutations.

Conclusions:

• The increased IRT levels in African-American infants during CF NBS are not clearly understood.
• Current screening protocols may lead to a high false-positive rate in this demographic.
• Implementing repeat IRT testing at 2-3 weeks could enhance screening specificity and reduce unnecessary follow-ups.