This is the amount of air that can be moved in and out as fast as you can in one minute. We ask the patient to breath as deep and as fast as possible for 10 seconds and express it for a minute. We take the best of 3 meaurements. Usually the first will be lower, the second and third effort will be similar. Lot of coaxing has to be done to encourage the patient to do the best. Click to see how it is performed (not yet).