The peak flow is mostly just used for asthmatics, cuz it measures if your airways are constricted.
My CF center used to check cystics 15 or 20 years ago w/ the separate peak flow meter...
buts its not as indicative of changes to the CF airways, as it would be to constriction that an asthmatic would have.
It doesn't measure a "volume of air"...it measures just a "flow"--the millisecond where in your FVC maneuver you hit the fastest/quickest point of "flow"
So unless you have an asthmatic component to your CF, I'm not sure your doc would rely on it much (at least at our CF center)
Like someone above said, for CF they mostly look at the FEV1 and FVC
By the way, the "peak flow" IS measured by normal PFTs...some reports just don't list it...
On the PFT it is usually called the "FEFmax" (forced expiratory flow maximum)
Look on your last PFTs, if it lists FEFmax it is the same as peak flow
FEFmax is in Liters/second though...so you have to multiply it by 60 to get the peak flow, which is measured as liters/min
james
30 w/cf
RT