The sweat test is the standard diagnostic test for cystic fibrosis. This simple and painless test measures the amount of salt in the sweat. A high salt level indicates that a person has cystic fibrosis. This test is usually given after the doctor has enough evidence to suspect the disease is present.

Some states screen newborn infants for Cystic Fibrosis. The screening is a simple blood test, often performed with other routine newborn testing. Blood is collected on a special card. Once the blood dries, the card is sent to a special laboratory for analysis.

Early detection of this genetic disease offers many benefits. Diagnosis in early infancy offers the opportunity for aggressive medical intervention and nutritional support that may prevent malnutrition and delay the onset of pulmonary complications. It may be possible with early detection and prompt intervention to reduce the number of hospitalizations and the cost of care associated with this life-limiting condition.Massachusetts and Wisconsin were the first states to implement screening. Currently newborn screening is available to the entire newborn population or a certain subset in eight of the fifty states. This initiative has spread worldwide to countries such as Australia and France.

Other tests such as genetic testing may be used to confirm the diagnosis of cystic fibrosis. The test is quick easy and painless only a fraction of the possible mutations is tested for the sensitivity of this test is suboptimal. All diagnostic and or confirmation testing must be done at an approved CF center.