Each disease is assigned an acuity: acute-severe (life-threatening), acute-moderate (not life-threatening), or subacute/chronic. The three levels of acuity are defined as follows:
The onset is acute, severe, and life threatening. The patient is likely to be admitted to the hospital.
The onset is acute, but not life threatening. The patient is likely to seek medical attention, but not be admitted to the hospital.
The onset of symptoms is gradual over a period longer than 2 weeks (subacute) or 2 months (chronic).