How did we gather this information? We posted the questionnaires and a saliva pot in which to put the sample. The instructions for collecting the saliva are also found here. We provided a reply paid envelope for return of the questionnaire and saliva pot.
For the skin prick test, breathing test and salivary cotinine, children and young people came to the hospital, either at a clinic or on a separate visit. It took about 30 minutes to do all the tests.