Here's why it's important to know your %ages:
1. Meds are coming to the market that have efficacy in certain FEV1% ranges. Example: denufosol has been shown to work only in patients with FEV1 >75%.
2. Existing meds on the market may have efficacy in different doses for certain FEV1% ranges. Example: Pulmozyme in patients with FEV1 > 85%
3. From my understanding (someone can correct me if I'm wrong), at a certain FEV1% range you are eligible for tx in certain tx clinics.
4. Certain clinical studies (which Dr. Beall says is one of the most important things for CFers to participate in in the coming years to ensure the meds we've been fundraising to develop will come to the market in a timely manner) will only admit patients within a certain FEV1% range.
So FEV1 % is far from irrelevant and I commend you for wanting to understand what your % is. It's very useful to know above and beyond the liter value.