Eating food or
drinks that contain caffeine before the test.
Not being able to
breathe normally because of pain.
Pregnancy, obesity, or an
enlarged stomach (after a large meal, for example).
Not being able
to follow instructions or make an effort during the tests.
What To Think About
Spirometry is the most commonly used lung
If your spirometry tests are normal but your doctor
thinks you may have
asthma, more tests may be done after you inhale
a substance (methacholine or histamine) that narrows (constricts) your airways.
This is called a bronchoprovocation test. It may be done while you sit in a
small airtight room (plethysmograph booth) similar to a telephone booth. The
amount of narrowing in your airways can help diagnose some conditions. This
testing may take as long as 2 hours.