The definition of WHO Functional Class

Means of classifying disease severity in PAH developed by the World Health Organisation and modified after the New York Heart Association functional classification according to level of function and associated symptoms. Increasing WHO FC reflects more severe symptoms and greater restriction in activity.

Please refer to Assessing the severity of PAH  where this term is mentioned.

If you are a patient and you have any questions about these definitions or how they apply to you, please contact your healthcare provider.