Methacholine Challenge

[labrat]

Hello,
How does the methacholine challenge work and what does it show, especially if former PFTs were normal?
Will caffeine alter the test results (for the better or worse)?
Thank you.

[Phix]

Hi.

I've had some trouble breathing a bit w/some chest pain.  anyway, I have to have this test done and im really nervous.  I've read basically what happens but my experience with testing hasn't been good.  The people usually dont really explain what will happen and are on you right away, just wanting to get it done.  Im trying to ask questions while they're doing this and they're so unfriendly!  Being friendly and willing to answer my questions would really help me, as a nervous patient.  I just wanted to know more about it before i have it done b/c I'm scared about it.

Thanks

[National Jewish]

Methacholine is a nonspecific irritant for the lungs. It is used to help in the diagnosis of asthma. It determines the level of hyperactivity of the airways, which is increased in asthmatics. Having normal lung function does not mean you do not have asthma and has no real bearing on how a Methacholine challenge will result. Caffeine is a stimulant that has minimal effect on the lungs. It has been shown to open the airways a small amount and really should not influence the result of a challenge to mask the diagnosis of asthma.
I hope this helps.