Table 2 Data of the 2011–2018 CF NBS algorithm: IRT1/IRT2 + LACT protocol and IRT1/DNA protocol separately

Newborns screened for CF

231,845

231,845

231,845

Newborns with negative screening

231,370

231,604

231,227

Non CF newborns with negative screening (TNs)

231,362

231,599

231,225

Number of retesting (IRT2)

906

–

906

Number of sweat tests (newborns with positive screening)

475

241

618

Number of sweat tests after positive IRT1 + LACT

157

–

–

Number of sweat tests after positive retesting (IRT2)

318

–

–

Non CF newborns with positive screening (FPs)

430

194

568

CF newborns with positive screening (TPs)

44

47

50

CF newborns with negative screening (FNs)

8

5

2

CF newborns diagnosed for meconium ileus

7

7

7

Sensitivity (%)

84.61^a

90.38^a

96.15

Specificity (%)

99.81^a

99.91^a

99.75

Positive predictive value (%)

9.26^a

19.50^a

8.09

Negative predictive value (%)

99.99^a

99.99^a

99.99