The usual method of investigating the changes that occur in asthma is to challenge the lungs. Samples have to then be collected from the lungs. This can be in the form of sputum which must be treated to break it down to a liquid or washed out during a camera test. These methods cause problems with measuring proteins and they are broken down or diluted. Because the nose is easily accessible samples can be obtained at many time points. Because the samples can be collected directly from the nose the problems with obtaining samples from the lung are avoided.