Table 1.

CF newborn screening algorithms.

IRT/IRT	Initial measurement of immunoreactive trypsinogen (IRT); elevated IRT results are repeated on a separately collected specimen on a different day.
IRT/DNA	Single elevated IRT is followed by DNA analysis from the same blood spot specimen to detect the most common CF variant(s).
IRT/IRT/DNA	Second elevated IRT is followed by DNA analysis from the same blood spot specimen to detect the most common CF variant(s).
IRT/DNA/NGS	Single elevated IRT is followed by DNA analysis from the same blood spot specimen to detect the most common CF variant(s). If 2 CF variants are not identified, the specimen is reflexed to next-generation sequencing of CFTR.

Description of the methodologies utilized for newborn screening in the United States. Next-generation sequencing technology in New York State includes analysis of the CFTR coding region, intron/exon boundaries, specific intron variants and large exon deletions/duplications (del/dup) using bioinformatics. Minimum sequencing coverage depth was 10×. Standard or real-time PCR was used to confirm large del/dup. All possible del/dup and variants deep in introns or the promoter regions are not detected by these methods.