What does a positive newborn CF screen mean?

What does the evidence say about a positive newborn cystic fibrosis screen?

1. The newborn blood-spot sample is a screening tool collected from the heel and processed by a laboratory. A result should be followed through to a documented plan. Ask who will arrange the next appointment and how you will receive the final interpretation. 1
2. CF screening commonly measures immunoreactive trypsinogen, or IRT, and may include selected CFTR variants. IRT can be elevated for reasons other than CF, including a stressful or premature birth. State testing methods differ, so obtain the actual report rather than interpreting the word positive alone. 2
3. A sweat chloride test stimulates a small area of skin and collects sweat for laboratory analysis. It does not rely on tasting the baby’s skin. The test center should provide preparation and scheduling instructions and explain whether additional testing is necessary. 3
4. CF is associated with variants in CFTR and can affect digestion, growth and breathing. A carrier finding and confirmed CF are different results. A genetics or CF specialist can explain the particular variant combination and what it means for the family. 4
5. A borderline sweat result, limited genetic panel or ongoing symptoms can require further assessment. Neither a screening label nor one isolated number should be interpreted without the complete context. Keep follow-up until the team has clearly documented the result and any continuing surveillance. 2

Following a screening result to a clear plan

• Obtain the actual report and confirm who is arranging the next appointment.
• Attend the sweat test or other assessment even if your baby looks well.
• Ask for the final interpretation and any ongoing monitoring in writing.