Self-treatment plan
| Step | Peak Flow | Symptoms | Action |
| 1 (green zone) | 80–100% PBV | No/intermittent/few | Continue maintenance treatment |
| 2 (yellow zone) | 60–80% PBV | Increased cough/wheezing/shortness of breath | Double the dose of inhaled steroids for 2 weeks |
| 3 (red zone) | 50–60% PBV | Nearly continuously shortness of breath and/or poor response to bronchodilator therapy | Prednisolone 30 mg·day−1 for 7 days |
| 4 (black zone) | <50% PBV | Severe attack of asthma | Call/visit physician/emergency room promptly |
PBV: personal best value. At all stages, take inhaled B2-agonists for relief of symptoms.