What diagnostic tests are commonly used to confirm cystic fibrosis?

The sweat chloride test and DNA testing are the primary diagnostic tools for confirming cystic fibrosis. The sweat chloride test measures the concentration of chloride in sweat; individuals with cystic fibrosis typically have elevated levels of chloride due to the defective CFTR (cystic fibrosis transmembrane conductance regulator) protein that affects salt transport in cells. This test is considered the gold standard for diagnosing cystic fibrosis.

DNA testing is utilized to identify mutations in the CFTR gene, further corroborating a diagnosis of cystic fibrosis. Identifying specific genetic mutations can also provide insight into the severity of the disease and help guide treatment options.

Other imaging modalities like X-ray and MRI, blood tests, CT scans, chest ultrasounds, and pulmonary function tests may provide supplemental information regarding the lung involvement or complications associated with cystic fibrosis but are not definitive diagnostic tests for the condition itself.