Being tested for asthma will typically include a medical history, including any pattern related to the symptoms or possible precipitating factors. Spirometry, which uses pulmonary function tests to study the air volume and flow rate within the lungs, can help detect asthma. Your doctor will look at vital capacity, peak expiratory flow rate and forced expiratory volume.
Weight gain while using Advair is something that has been discussed a lot in asthma communities, as you can see here and here and here and here and here and here. Yet there has been very little documented evidence as to whether it is true or not. I was recently asked, "Does Advair cause weight gain?" My answer here was a…