Diagnosis

To diagnose cystic fibrosis, doctors typically do a physical exam, review your symptoms and conduct several tests.

Newborn screening and diagnosis

Every state in the U.S. now routinely screens newborns for cystic fibrosis. Early diagnosis means that treatment can begin immediately.

In one screening test, a blood sample is checked for higher than normal levels of a chemical called immunoreactive trypsinogen (IRT), which is released by the pancreas. A newborn's IRT levels may be high because of premature birth or a stressful delivery. For that reason, other tests may be needed to confirm a diagnosis of cystic fibrosis.

To evaluate if an infant has cystic fibrosis, doctors may also conduct a sweat test once the infant is at least 2 weeks old. A sweat-producing chemical is applied to a small area of skin. Then the sweat is collected to test it and see if it's saltier than normal. Testing done at a care center accredited by the Cystic Fibrosis Foundation helps ensure reliable results.

Doctors may also recommend genetic tests for specific defects on the gene responsible for cystic fibrosis. Genetic tests may be used in addition to checking the IRT levels to confirm the diagnosis.

Testing of older children and adults

Cystic fibrosis tests may be recommended for older children and adults who weren't screened at birth. Your doctor may suggest genetic and sweat tests for CF if you have recurring bouts of an inflamed pancreas, nasal polyps, chronic sinus or lung infections, bronchiectasis, or male infertility.