Last poster again - Just wanted to say that besides asking for the cilia biopsy, I'd request genetic testing for cf through Ambry. More than likely your genetic test was through one of the other labs like genzyme which only test for the most common mutations. If you do have cf and had a truelly negative sweat test, then you'd be more likely to have a rare mutation that would be picked up on those panels. I'd request both. And, no, I'm not a cf patient or parent of a cf patient. Just a parent who has done tons of research, seen multiple pulmonologists, ENTs, and allergists and is still seeking a diagnosis for my child. Like you he has had a negative sweat test and negative genetic test through genzyme. When he has his next sinus surgery, the ENT will be doing the ciliary biopsy. Not before because they put children under general anesthesia. We'd rather wait and have them done together. (He's 6 yrs old, this will be his second sinus sugery). One more thing, do you have problems with sinusitis? Chronic sinusitis is pretty much a universal symptom of people with PCD.