How well controlled is your asthma right now? That single question shapes everything: whether your treatment plan still fits, whether environmental triggers are creeping in, and whether you need a clinic visit. The Asthma Control Test (ACT) answers it in five questions.
This guide walks you through the ACT — what it measures, what each score range means, and what to do next based on your result. We also place the ACT in context: how it complements lung function, fitness, and other health markers.
What is the ACT?
The Asthma Control Test was published by Nathan and colleagues in the Journal of Allergy and Clinical Immunology in 2004 and has been validated in dozens of studies since. The Global Initiative for Asthma (GINA) recommends it as a longitudinal monitoring tool.
Five questions, scored 1–5 each. Reference period: the past four weeks. Total score: 5 to 25.
The five ACT questions
- Activity limitation — How often did asthma keep you from getting things done at work, school, or home?
- Shortness of breath — How often have you been short of breath?
- Nighttime symptoms — How often did asthma wake you up at night or earlier than usual?
- Rescue inhaler use — How often have you used your SABA (albuterol/salbutamol)?
- Self-rating — How would you rate your overall asthma control?
Score ranges
| Score | Meaning | Suggested action |
|---|---|---|
| 20 – 25 | Well controlled | Maintain therapy and trigger avoidance |
| 16 – 19 | Not well controlled | Discuss therapy adjustment with your doctor |
| 5 – 15 | Poorly controlled | Seek medical review promptly |
A change of ≥ 3 points is considered clinically meaningful (MCID, Schatz et al. 2009). Trends across multiple ACTs carry more weight than a single value.
What the ACT does not replace
The ACT captures symptoms, not lung function. Spirometry (FEV1) or peak flow complements the score. A reassuring ACT (e.g. 22) paired with a low FEV1 is a red flag — patients often underestimate their symptoms (Schatz 2006).
The ACT also does not assess exacerbation risk directly. Frequent oral steroid courses or hospital visits are independent warning signs even if the ACT looks fine.
What to do based on your score
- Score < 20: book a primary care or pulmonology visit — usually a step-up in controller therapy by GINA stage is enough.
- Rescue inhaler > 2× per week: a clear sign that controller therapy is too light. Overuse increases exacerbation risk.
- Identify triggers: pollen, animal dander, smoke, exercise, infections. A 2-week asthma diary surfaces personal triggers reliably.
- Check inhaler technique: up to 70% of patients inhale incorrectly. A 2-minute review at the pharmacy or clinic.
Related topics & calculators
- VO₂max — maximum oxygen uptake stays normal in well-controlled asthma. A noticeable drop suggests further lung-function workup. See the VO₂max guide.
- Heart-rate zones — exercise-induced asthma is common; targeted training zones help keep symptoms manageable. See the heart-rate guide.
- Vitamin D — vitamin D deficiency is associated with higher asthma activity (Cochrane 2016). See the vitamin D guide.
Take the ACT now
Five questions, instant score, anonymous. Get a clear read on how well your asthma was controlled over the past 4 weeks.
Open the Asthma Control Test →Frequently asked questions
How often should I take the ACT?
Every three months when stable. Weekly during therapy changes or after an exacerbation. Watching the trend is more informative than any single value.
My score is below 16 — is this an emergency?
No, a low score is not an emergency, but it is a clear signal of insufficient control. Schedule a clinic visit soon. For acute breathlessness or rapid worsening, ignore the score and seek medical help or call emergency services.
Does the ACT work for children?
The ACT shown here is validated for ages 12 and up. For children aged 4–11 use the Childhood ACT (cACT), which is age-appropriate and includes a parent-rated component.
What role do triggers play?
Triggers often explain sudden score drops. Common ones: respiratory infections, pollen, pet allergens, smoke, cold air, exercise. A two-week asthma diary usually reveals personal patterns.