There are many techniques that can allow for the quantification of lung function in children; some are being used clinically and others are under development. Many of these tools are available at BC Children's Hospital. This registry study will act as a central repository for the results of traditional and novel pulmonary function tests done at BC Children's Hospital to allow for future analysis.

The scope of the registry is to collect data on small airways function in healthy children, children with cystic fibrosis (CF) and children with non-CF respiratory disease using the multiple breath washout (MBW) system. These data will be stored along with demographic data, clinical data, and traditional pulmonary function testing (PFT) data. The MBW data will be collected with concurrent with clinically indicated PFT testing.

The purpose of the registry is to 1/ establish a locally collected normal range of small airways function across the paediatric age range and 2/ to collect these measurements in CF and non-CF respiratory disease.

Ultimately, the objective of this registry is to validate MBW technology as a tool that can be utilized in clinical care.

Participants with CF

Inclusion Criteria:

-Diagnosis of CF as evidenced by one or more clinical feature consistent with the CF phenotype or positive CF newborn screen AND one or more of the following criteria: i. A documented sweat chloride ≥ 60 mEq/L by quantitative pilocarpine iontophoresis (QPIT).

ii. A documented genotype with two disease-causing mutations in the CFTR gene.

- In the opinion of the investigator, the participant will likely have the ability to perform the lung function test of interest on the day of testing

Exclusion Criteria:

• Physical findings at the screening that would compromise the safety of the participant or the quality of the data (e.g. respiratory distress or work of breathing)
• Requirement of supplementary oxygen to maintain oxygen saturation above 95%

Participants with other Respiratory Disease

Inclusion criteria:

• Physician-diagnosed lung disease
• Informed consent by participant, parent, or legal guardian
• In the opinion of the investigator, the participant will likely have the ability to perform the lung function test of interest on the day of testing

Exclusion criteria

• Physical findings at screening that would compromise the safety of the participant or the quality of the research data
• Requirement of supplementary oxygen to maintain oxygen saturation above 95%

Healthy Participants

• Inclusion criteria
• Informed consent by participant, parent, or legal guardian
• In the opinion of the investigator, the participant will likely have the ability to perform the lung function test of interest on the day of testing

Exclusion criteria

• Physical findings at screening that would compromise the safety of the participant or the quality of the research data
• Evidence of lung disease

Participants with CF Participants with other Respiratory Disease Healthy Participants

MRH-Registry Data may be shared with investigators from BCCHR/UBC or elsewhere. MRH-Registry Co-Investigators using MRH Registry Data to address the Scientific Objectives of the MRH Registry do not need to formally apply for access. All other User-Investigators (domestic and international) must apply to the MRH-Registry Data Access Committee for access to the MRH-Registry Data.

Criteria for access to the MRH-Registry Data:

The Proposed Study must demonstrate approval by a Qualified REB The objectives of the Proposed Study must align with the scientific objectives of the iMRH-Registry Use of the MRH Registry Data in the Proposed Study must respect the informed consent given by the participants of the iMRH Registry; The Proposed Study must have scientific merit, as assessed by the MRH Registry Data Access Committee The User-Investigator must demonstrate sufficient funding to perform the Proposed Study.