Coding Asthma for pediatrics

Does anyone know of any specific requirements/testing that need to be done before a diagnosis of Asthma should be given? I have a physician that diagnosis a child with asthma when they come in for a cough/congestion. I was told a long time ago that PFT's or some type of testing needed to be done to be able to properly diagnosis asthma. I don't have any supporting documentation to back this up.

re: Coding Asthma for pediatrics

I would think that the provider would have to at least perform some kind of pulmonary dignostic testing for air flow such as a spirometry codes 94010, 94011 or 94012, 94013, just a thought:)