pulmonary function test question

I had a pulmonary function test done and most of it came back normal (terms I don't understand but I understand "normal." The note said however that "patient did have inspriatory volume less than 85% of vital capacity for the DLCO maneuver."

What does that mean? It also said "Diffusion suggestive of asthma."

My lung xray came back normal.

Thanks if you can shed any light on this for me.