Cough swabs and sputum samples

Information for children, teenagers and families

Cough swabs and sputum samples

Infections in the airway are the cause of lung damage in CF. The presence of an infection is detected if your child has a cough and/or a positive airway culture result. Airway samples are collected at all routine clinic visits and during chest exacerbations. Many children, particularly young children cannot produce a sputum sample. For these children we will collect a cough swab. This is a swab on a stick which is held as far back in the throat as possible while the child coughs. In very young children who cannot cough on request, we will rub the swab on the back of the throat, ideally immediately after the child has coughed.

Bacteria growing on an agar plate

Once the sample (sputum or cough swab) has been collected it is sent to the microbiology lab in the hospital. The lab put the samples on special plates to see if any bacteria or fungi grow from sample. This test will not detect viruses we don't routinely test for viruses since there are no medicines that are effective in treating viral infections. The results from the lab take 7 days for most bacteria, upto 2 weeks for the fungi and for one particular type of bacteria, called NTM, upto 7 weeks. Often the samples will be negative. If the sample is positive, it will most likely grow one of the bugs described on the 'bugs' page.