Does Spiriva affect pft results?

I'll try to be brief. My dr. ordered a pft last week (following three ct scans over 16 months). I had been using Spiriva for three years. My question is how long should I have been off the Spiriva for the test to show accurate results? Shouldn't I have had the test before being given Spiriva? Thanks in advance.

[National Jewish Health]

Spiriva® HandiHaler® (tiotropium bromide inhalation powder) has a maximum duration of action of about 36 hours.  To be safe, you would want to be off the medicine for 48 to 72 hours before the spirometry.  It would have been preferable, but not mandatory to do the pulmonary function tests (PFTs) at the time the diagnosis of chronic lung disease was made especially if the diagnosis was unequivocal.  The other important question would be, “Why 3 CT scans, presumably of your lungs, in 16 months?  You should ask your doctor about this.  It may be time for you to see a lung specialist.

[shurely]

Thank you for your reply. I had the CT scans because of nodules in my left lung. The findings of the last one were : a cluster of calcified granulomata are again seen in the left lower lobe with calcified nodes in the left hilum and to a lesser extent mediastinum. A few granulomata are also seen in the spleen. There are again 2 tiny nodules seen associated with major fissure on the left side. Small 3 or 4 mm pleural based nodule is again seen in the right middle lobe. Some patchy scar and consolidative like changes are seen in the medial segment of the right middle lobe adjacent to the mediastinum. Findings are similar to prior exam. Can you tell me if this is something I should see a specialist about? Also, the results to my PFT showed no obstructive or restrictive abnormality. Diffusing capacity and residual volume are within normal limits and showed no response to bronchodilator therapy. They told me to stop the Spiriva. Thank you again for your help. By the way, I'm a 41 yr old female.