Describe the newborn screening.
Newborn screening (NBS) for CF is essential for early detection and treatment, which can improve health outcomes. In many countries, including the US, it is mandatory to screen for CF. 
Sample collection: newborn blood spot test, performed via heel prick blood sampling in the first 24 and 48 hours of life
Screening tests 
Immunoreactive trypsinogen (IRT) : initial screening test
An immunofluorescence assay that measures levels of IRT 
Normal IRT levels: CF unlikely
Elevated IRT levels: CF possible; additional screening tests required 
CFTR mutation testing (DNA testing): second-tier screening test
Identifies the most common CF-causing CFTR mutations, including CF carriers
Cannot detect uncommon CFTR mutations that are not included on the panel.
Screening protocols: a combination of CF screening methods to minimize false-positive and false-negative NBS results 
Next steps after positive NBS: Refer patients promptly to a specialist for a complete diagnostic workup and to start treatment if required.