Because irreversible damage to the cystic fibrosis (CF) lung is already observed in infancy, a need has arisen to assess and monitor lung function early in life. Infant lung function testing (ILFT) is non-invasive, does not require radiation or anaesthesia and can be repeated frequently; therefore, development, standardisation and validation of techniques, protocols and equipment have received priority. Thanks to the hard work of many researchers across the globe during the last few decades, we are now able to study and compare development of lung function in the youngest during health and disease.1Through standardisation, and the use of appropriate reference populations, we can now collate data from different centres to find reliable answers to basic questions on developmental physiology1 ,2 and to study lung function growth in chronic lung disease.3–5

The study by Nguyen et al 6 illustrates the value of such collaboration. Rather than competing with one another, the 6 CF centres of The London CF Collaboration (LCFC) shared protocols for treatment and follow-up. As a result, a relatively large group of infants with CF treated, diagnosed through NewBorn Screening (NBS) according to a standardised regimen could be analysed in relatively short period of time. ILFT was assessed in one specialised centre with sufficient experience and capacity to carry out longitudinal ILFT measurements. Moreover, healthy controls of about the same age were measured as well, serving as an adequate control group.

Lung function was below average …