Comparing PFT's

[strdsbrg]

I had one PFT performed in 2003 when I was 36 years old and another in 2007.  Different labs.  I am male and had smoked about a half a pack a day for 25 years.  I have since quit, but smoked up through the second PFT.  On the first test, the report indicated that the technician used .5 for the number of packs per day (which was accurate).  For the second test, it seems the technician put in 1 pack per day.  Are the results incomparable because of this and things like the changes in predicted values?  If the 2007 technician had put in that I smoked only .5 packs a day - the correct amount - is it true that my results would have probably been much worse?  For example, my FEV1/FVC ratio was the same on both tests, but in actuality it probably changed and because of this error, the test does not indicate that.

Could someone please elaborate on the change in my results taking into account the forementioned information.  I am very worried.  Thank you for your help.

2003  
FVC  117%predicted
FEV1  110%predicted
FEV1/FVC 72 (94%predicted - the predicted was only 77)

2007
FVC 102%predicted
FEV1 89%predicted
FEV1/FVC 72 (87%predicted - the predicted was 82)

[National Jewish Health]

These tests are normal.  They are reflections of the effort you performed in doing the test and not in what you told someone or was recorded. The changes in the results may or may not be related to the fact that you have smoked over a period of time.  While there is a decrease in the 2007 tests, these results are still within the normal range.  Stopping smoking is a good thing and should be applauded and continued.

[Between]

It looks to me like your lung function is declining from smoking. You still have good lung function by those numbers but if you continue to smoke they will continue to drop. Don't go back to smoking and make sure you keep active. You will be fine.