Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek urgent or emergency care for severe difficulty breathing, blue or gray lips, fainting, confusion, coughing up more than a small streak of blood, severe dehydration, sudden chest pain with breathlessness, persistent vomiting, or severe abdominal swelling with inability to pass stool or gas.
Follow the emergency plan provided by the person’s CF team.
Contact the CF team promptly for a clear increase in cough or mucus, fever, reduced appetite, weight loss, unusual fatigue, new shortness of breath, vomiting, worsening constipation, or reduced ability to complete usual activities.
Early review may prevent a manageable problem from becoming more serious.
Routine follow-up usually includes regular visits with the CF care team, even when the person feels well.
Visits may involve weight and growth measurements, breathing tests, respiratory cultures, treatment review, and discussion of nutrition, exercise, sleep, mental health, school, work, or family planning.
The article also says
Periodic blood tests and other assessments may monitor vitamin levels, liver health, blood sugar, bone health, medication effects, and complications.
The exact schedule depends on age, symptoms, treatments, and clinical findings.
Every sign above is quoted from the sofidex article on Cystic fibrosis. If you are not sure, err upward — it is always reasonable to be checked.