My 5 yr old little boy has suffered fatigue and weight loss now 112cm and down to 14kg (although over the last two weeks and twice daily milkshakes/nutrition supplements he is now back to 15kg) and is suffering from recurrent pnuemonia symptoms which does not show up as pnuemonia on xray. Twice requiring ambulance transfers to hospital and week long admissions. This lasts for a few weeks generally each time. He is very pale and tired. Xray shows peribronchial inflammation or cuffing and diffuse mucous. No wheeze. Oxygen saturation levels when he gets these infections drop below 80%. His new paediatrician has mentioned cystic fibrosis but his case conference fellows have just decided that since there is no damage on the X-rays that this is now not likely. I m feeling uneasy about not having a definite answer. Should I be pushing for a sweat test for a definitive answer or in your opinion does CF not sound likely?