I too have CF and had previous been diagnosed with Sarcoidosis.
After an abnormal chest X-ray in 1980 at the age of 39 I was diagnosed with Sarcoidosis. The diagnosis was made with the Kveim test. A 1990 chest X-ray revealed Bronchectesis, which a "quack" doctor first said it might be a flare up of the Sarcoidosis. It was not until 2005, that I was diagnosed with CF via genetic testing at National Jewish in Denver CO.
Although I had productive caught, sinus problems, and low grade fevers all my life, sweat tests were always negative. The CF diagnoses at the age of 63 was a real blessing, thank G-d. The drugs that became available have really improved my quality of life.
As far as the Sarcoidosis, I never experienced any symptoms (except for the chest X-ray) and it never required treatment. No one at the three adult CF centers in New York that I've visited ever mentioned being aware of a link between Sarcoidosis and CF.
To all: I would recommend a visit to National Jewish Health to anyone with a lung condition who wants a second (or third or fourth or ...) opinion. When I traveled to Denver in 2005, I had previously been to more than 8 specialists at major New York hospitals. That trip to Denver was a real life changer!
Stephen, 70 y/o
FEV1 48%, otherwise feel great, thank G-d.