In the green zone, which statement best describes the PEF range?

• A. PEF 60-70% of personal best
• B. PEF 50-79% of personal best
• C. PEF <50% of personal best
• D. PEF 80-100% of personal best

Answer: (D)

Green zone means your peak expiratory flow is 80–100% of your personal best. Personal best is the highest PEF you can achieve when your asthma is well controlled, and it serves as your target range. When you’re in this green range, airways are functioning well and you should continue your current treatment plan without changing medications. It’s a cue to keep up daily controller meds and use your rescue inhaler only if symptoms arise, since you’re within your optimal range.

Numbers outside this range point to other levels of control: 50–79% is a yellow zone, indicating partial control where you may need to use the rescue inhaler and possibly adjust therapy; less than 50% is a red zone requiring prompt action and often urgent evaluation.