A doctor may use CF gene mutation testing to rule out CF if the patient has symptoms such as salty sweat, persistent respiratory infections, wheezing, persistent diarrhoea, foul-smelling bulky greasy stools, malnutrition and vitamin deficiency.
CF gene mutation testing may also be used to confirm a CF diagnosis following a positive sweat chloride or IRT test. CF gene mutation testing may also be used to determine CF carrier status.
If the CF gene mutation test is positive - it comes back with two identified gene mutations - then the patient has CF. The test, however, cannot tell how severe or mild the symptoms may be. Patients with the exact same mutations may have very different outcomes.
If the test comes back negative for mutations and the patient is asymptomatic, chances are that they do not have CF and are not a carrier. There is still a slight risk that the person could be a carrier of a rare mutation not picked up with the standard testing.
If the CF gene mutation test is negative and the patient is symptomatic, the doctor may recommend further genetic testing, a sweat chloride test, and other laboratory testing to check organ function. The patient may have a more rare form of CF that is not being identified or may have a lung or pancreatic disease or condition other than cystic fibrosis.
If the CF gene mutation test comes back with a single identified mutation and the patient is asymptomatic, then chances are that the person is a CF carrier. This may be information some individuals want to know before having children. If you are identified as a carrier, your siblings may also want to verify their carrier status.
Early detection of cystic fibrosis is important. It enables people to be referred to specialist care and begin treatments such as taking oral enzyme supplements and fat-soluble vitamins. Also, by learning how to clear mucus out of airways and learning to recognise respiratory infections a person's quality of life can be improved and CF complications minimised.