Nutrient supplementation
It is uncertain whether vitamin A or beta-carotene supplementation have any effect on eye and skin problems caused by vitamin A deficiency.There is no strong evidence that people with cystic fibrosis can prevent osteoporosis by increasing their intake of vitamin D.For people with vitamin E deficiency and cystic fibrosis, there is evidence that vitamin E supplementation may improve vitamin E levels, although it is still uncertain what effect supplementation has on vitamin E‐specific deficiency disorders or on lung function.Robust evidence regarding the effects of vitamin K supplementation in people with cystic fibrosis is lacking as of 2020.Various studies have examined the effects of omega-3 fatty acid supplementation for people with cystic fibrosis but the evidence is uncertain whether it has any benefits or adverse effects. Procedures
Several mechanical techniques are used to dislodge sputum and encourage its expectoration. One technique good for short-term airway clearance is chest physiotherapy where a respiratory therapist percusses an individuals chest by hand several times a day, to loosen up secretions. This "percussive effect" can be administered also through specific devices that use chest wall oscillation or intrapulmonary percussive ventilator. Other methods such as biphasic cuirass ventilation, and associated clearance mode available in such devices, integrate a cough assistance phase, as well as a vibration phase for dislodging secretions. These are portable and adapted for home use.Another technique is positive expiratory pressure physiotherapy that consists of providing a back pressure to the airways during expiration.
An electric current is used to drive pilocarpine into the skin, stimulating sweating. The sweat is collected and analyzed for salt levels. Having unusually high levels of chloride in the sweat suggests CFTR is dysfunctional; the person is then diagnosed with cystic fibrosis. Genetic testing is also available to identify the CFTR mutations typically associated with cystic fibrosis. Many laboratories can test for the 30–96 most common CFTR mutations, which can identify over 90% of people with cystic fibrosis.People with CF have less thiocyanate and hypothiocyanite in their saliva and mucus (Banfi et al.). In the case of milder forms of CF, transepithelial potential difference measurements can be helpful. CF can also be diagnosed by identification of mutations in the CFTR gene.In many cases, a parent makes the diagnosis because the infant tastes salty. Immunoreactive trypsinogen levels can be increased in individuals who have a single mutated copy of the CFTR gene (carriers) or, in rare instances, in individuals with two normal copies of the CFTR gene. Due to these false positives, CF screening in newborns can be controversial.By 2010 every US state had instituted newborn screening programs   and as of 2016, 21 European countries had programs in at least some regions. Prenatal
Women who are pregnant or couples planning a pregnancy can have themselves tested for the CFTR gene mutations to determine the risk that their child will be born with CF.