We recently changed hospitals and specialists. My son was for the first time earlier this year, given a full Pulmonary Function Test - blowing into a device connected to some software on a PC. For the first time ever we saw how his FEV1 (amount he can blow in first second) was only 72% of what it should have been.
6 months later (today) and with him having the remains of a cold, his FEV1 was 93%. This is also the first time ever that he has had a cold with no asthma wheezing, coughing or other symptoms. To put this in perspective - he usually ends up in hospital 2 or 3 times a year and EVERY cold has given him an asthma attack.
The reason for the improvement is that since the full test, he's maintained a strict regime of Symbicort all summer and he also doubles his dosage when someone else in the house or he gets a cold.
Everyone should have access to full allergy and lung function tests.