Brief Answer:
PFT is used to Dx COPD , ILD, not Lung Cancer
Detailed Answer:
Dear Mam
Without looking at X- Ray it would be difficut to comment upon the cause.
But history is suggestive of
bronchitis. Since you have
sinusitis also , that can also contribute to the infection. yellow mucous is suggestive of some infection , that probably
Levaquin must have covered.
PFT means Pulmonary Function Tests. PFT is helpful in finding whether you have restrictive or
obstructive lung disease, like COPD (chronic bronchitis and or
emphysema),
bronchiectasis , interstitial lung disease.
Since you have been a smoker , it would be a wise decision to rule out these conditions.
Your doctor said there is air left in the lung , this means
pneumothorax , but that can't be in your case as your doctor would have promptly admitted you.
By saying those words and asking you for PFT , probably she wants to rule out some disease like bronchiectasis , COPD.
From so far, i can tell you that if your doctor has asked you for PFT , she is not thinking of Lung cancer , as PFT is not a diagnostic modality for lung cancer.
Go for PFT , let your doctor diagnose and get treated.
Get Well Soon.
I hope i am able to answer your query , still if you have any query , ask me.