Forced Expiratory Volume in the first second: FEV1. It's a measure of how much air you can blow out in the first second of blowing. It's measured in liters and is part of a spirometry or Pulmonary Function Test. It's usually referred to as a percentage: what you can blow out compared to someone with no lung disease who is your height, weight, age, sex and ethnicity. My FEV1 is usually in the mid 30s so I tell people I have about a third the lung function of my counterpart who doesn't have lung disease.

Like everything else in a PFT or spirometry test, the results are based on percentages. The goal is 100%, but not many results meet that standard, so there are ranges. 33% is in the lower third. Maybe this helps put it in perspective for you. Even though that number may seem low, part of what's important to remember is that any one number by itself may be indicative of something, but it's usually not the only thing to consider when looking at test results. That's why it's important to have someone who really understands what the numbers mean when taken all together, and why not every diagnosis is for COPS. Sometimes the numbers point to another diagnosis altogether.

Thanks Jean.I could google it but I find you keep things on a level the average person can understand.I googled Diffusion but couldnt understand where my 33% stood ,is it really low or average.

Thanks ICC for the info.Take care

Thanks Jean,sorry to keep bothering you but now i feel i have a better understanding so when i talk to Dr.I no what to ask.and maybe I will understand her better