What IS MY functional class?
Functional class is one way doctors assess the severity of your PAH symptoms.
The World Health Organization (WHO) created a system of 4 “functional classes” (FC) for patients with PAH. Class I means fewer symptoms and less restriction of activity. Class I symptoms are considered the least severe, and Class IV symptoms the most severe. Here are some basic criteria for each FC:
No symptoms with ordinary physical activity.
Symptoms with ordinary activity. Slight limitation of activity.
Symptoms with less than ordinary activity. Marked limitation of activity.
Symptoms with any activity or even at rest.