What does the red zone on a peak flow meter indicate?

• A. Green zone indicates asthma is under control
• B. Yellow zone indicates caution; symptoms are getting worse
• C. Red zone indicates emergency treatment if symptoms do not improve after rescue meds
• D. Blue zone indicates no symptoms

Answer: (C)

Red zone signals a dangerous level of airway constriction and urgent action is needed. When the peak flow reading falls into this zone, it means asthma control has deteriorated and there is a high risk of a severe attack. The recommended course is to use a fast-acting inhaled bronchodilator (rescue medication) immediately. If there is no improvement after a short period, seek emergency medical care right away. This zone is the alert to escalate treatment rather than wait and see. For context, green indicates good control and yellow indicates caution; the red zone is the distress signal indicating you must act quickly.