Can a simple breath test diagnose diseases in children?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age 0 ≤ 22 years at study entry and signed informed consent Additional inclusion criteria for respiratory disease population: * Acute disease: - Acute signs for a respiratory disease, indicated by e.g. increased work of breathing (e.g. dyspnea, increased respiratory rate), cough or wheezing. * Chronic disease: - Suspected or confirmed chronic airway disease (e.g. asthma). Additional inclusion criteria for neurological disease population: * Acute disease: - Acute presentation or report within 24 hours of any signs of neurological deficit (motor function, sensoneural, or verbal). * Chronic disease: - Confirmed chronic neurologic disease (e.g. childhood epilepsy). Additional inclusion criteria for T1D disease population: * Acute disease: - Hyperglycemia and/or pH (venous) \<7.3, bicarbonate \>10 mmol/L, increased levels of acetone in blood or urine in the context of newly diagnosed or known T1D. * Chronic disease: - Confirmed diagnosis of T1D Exclusion Criteria: * Physical or intellectual impairment precluding protocol adherence. Additional exclusion criteria for respiratory disease population: * Known malignancy, active smoker (passive smoke exposure is not an exclusion criterium), known inflammatory diseases (e.g. autoimmune disease) that require medical and/or pharmacological treatment and is associated with an inflammatory response, relevant congenital defects Additional exclusion criteria for neurological disease population: * Known malignancy, active smoker (passive smoke exposure is not an exclusion criterium), known inflammatory diseases (e.g. autoimmune disease) that require medical and/or pharmacological treatment and is associated with an inflammatory response, relevant congenital defects. Additional exclusion criteria for T1D population: * Known malignancy, active smoker (passive smoke exposure is not an exclusion criterium), relevant congenital defects.