S.H.
The Spirometry itself, cannot diagnose Asthma.
Did you see a Pulmonologist or the regular Pediatrician?
A specialist, should be seen.
I have Asthma.
Since childhood.
http://asthma.about.com/od/adultasthma/a/art_AA_spiro.htm
http://www.medgraph.com/aboutasthma.html