Inclusion Criteria:

• Having undergone an right heart catheterization (RHC) within 18 months (prevalent PH participants) or 6 months (prevalent non-PH participants) or have undergone or planned RHC within 6 weeks (incident participants). The results of the incident RHC (incident participants) or the most recent RHC (prevalent participants) will be used to classify the participant in one of the above study population categories.
• Medically stable on the basis of physical examination, medical history and vital signs performed at screening. Any abnormalities must be consistent with the underlying illness in the study population and this determination must be recorded in the participant's source documents and initialed by the investigator.
• Must sign an Informed Consent Form (ICF) (or their legally acceptable representative must sign) indicating that he or she understands the purpose of, and procedures required for, the study and is willing to participate in the study.
• Must sign a separate ICF (or their legally-acceptable representative must sign) if he or she agrees to provide an optional (deoxyribonucleic acid [DNA]) sample for research (where local regulations permit). Refusal to give consent for the optional (DNA) research sample does not exclude a participant from participation in the study.

Exclusion Criteria:

• Participants requiring renal dialysis.
• History of lung or heart transplant (waiting list status or consideration of enlisting is allowed).
• Participants unable to breathe room air without supplemental oxygen for at least 10 minutes (for breath collection).
• Severe left ventricular dysfunction: Left ventricular ejection function less then (<) 35 percent (%).
• Participants who are immunocompromised.