This is a method of extracting cells from your breathing tract. Hypertonic (very salty) water is nebulised for about 5 minutes which usually causes individuals to cough and to produce some mucus from their lower airways.

We can use these specimens to test for unusual infections (e.g. pulmonary tuberculosis) or to find out what inflammatory cells are present. A finding of >3% eosinophils suggests  asthma whereas greater than 60% neutrophils is likely to indicate bacterial infection.

This test can be very helpful in determining the nature of your chronic cough or your recurrent episodes of bronchitis or asthma.