Title page
Contents
About Public Health England 2
Introduction 4
1. Processing positive results from CF newborn blood spot screening 5
a) Two CFTR mutations detected on the first blood spot sample - CF suspected 5
b) One CFTR mutation detected and raised second IRT - CF suspected 9
c) No CFTR mutation detected but very high (≥ 99.9th centile) first IRT and raised second IRT - CF suspected 9
d) One CFTR mutation detected and normal second IRT - probable carrier, low likelihood of CF 9
e) No CFTR mutation detected, very high first IRT (≥ 99.9th centile) but normal second IRT - CF not suspected 11
2. Evaluation and management of babies with an unclear diagnosis after CF newborn blood spot screening 12
a) Cystic fibrosis screen positive, inconclusive diagnosis (CFSPID) 12
Supporting information and letter templates 13
References 14
Appendix 1: Communicating screening results to parents: CF is suspected (two mutations detected on first blood spot sample) 15
Appendix 2: Communicating screening results to parents: CF is suspected (one or no mutations detected on second IRT) 17
Appendix 3: Communicating screening results to parents: carrier of CF gene 19