How often should a person take the "Gold" test that identifies your lung capacity ?

First took the test about 20 months ago.

Scores were in the high 70's then.

Was told that I had asthma and emphasema.

Since the exam I have lost 12 pounds.

Qvar has done wonders for me.

But gradually I am able to exercise less and less.

Should I take the exam a second time or just wait for

the oxygen phase to set in?

Thanks,

Ed Fuchs