It usually takes three or four days to run a sputum culture, which is why it's not done when you first present. After all, you don't want to wait three or four days; if you have COPD, without appropriate treatment and a nasty bug, you might not survive the experience. Not worth it! Docs know enough about sputum and when they ask what color it is, that tells them a lot. Most of the time it's yellow or green and that indicates an infection and lots of white blood cells giving their lives in the fight. Zpacks are a fairly broad spectrum antibiotic and will likely work on pretty much any bug. If the bug persists, then it's time for that sputum culture while you try other broad spectrum antibiotics or a larger dose of the Zpack. Ask your doc this question and see what she says. And ask yourself if you want to pay for something that might be unnecessary.

My Doctor after two years I've been asking for tests on sputum finally did it...I am diagnosed now with Non-Tuberculosis Mycobacteria disease...Need various anti-biotic treatments for a year-year and a half...so have that done. It's tested in culture.

Ermm......What IS a Zpack.....? Never heard of it. I'm assuming it's an American thing. I'm in the UK. I have quite advanced COPD. I'm allergic to Penicillin. Whenever I develop any kind of infection, my GP has to carefully consider what antibiotic he can safely prescribe. I'm sure that there are some drugs that are actually the same, but have different brand names in the UK to those under which they're known in the US.
P.S; what the HECK is a, 'GIF.....?'

Sputum tests and antibiotics are a waste if time. We have COPD. I've wasted too much time railing against ity - trying to find a, 'fix.' Now, I just accept that my life isn't going to be what I thought it would be. Some things one cannot fight. Best not to waste what time one has. Take what you have. Forget doctors & tests. I went through HELL undergoing tests. Hasn't made any difference. I'm where I am.