Asthma Control Test (ACT) Calculator

questionnaire

In the past 4 weeks, how much of the time did your asthma keep you from getting as much done at work, school, or at home?

During the past 4 weeks, how often have you had shortness of breath?

During the past 4 weeks, how often did your asthma symptoms wake you up at night or earlier than usual?

During the past 4 weeks, how often have you used your rescue inhaler (e.g., salbutamol)?

How would you rate your asthma control during the past 4 weeks?

✓ when to use

Use at every asthma review to assess control and guide treatment decisions. ACT ≥20 = well controlled (consider step-down if sustained), 16–19 = not well controlled (review and consider step-up), ≤15 = very poorly controlled (urgent review). Administer before the consultation for most efficient use.

✗ when not to use

ACT reflects a 4-week recall period. It does not capture acute exacerbations in real-time and should not be used to guide acute asthma management. Scores may be influenced by comorbidities (allergic rhinitis, GORD, obesity) that contribute to respiratory symptoms. Not validated in children <12 (use Childhood ACT for ages 4–11).

clinical pearls

ACT ≥20 = well controlled. This is the number to remember. Below 20, something needs to change — but always check technique and adherence before changing medication.
The ACT is scored 5–25 (not 0–25) because each item scores 1–5, not 0–4. A score of 5 represents the worst possible control across all domains.
A 3-point change is clinically meaningful. When tracking response to treatment changes, look for ≥3-point improvement rather than small fluctuations.
Before stepping up asthma treatment based on a poor ACT score, always check: inhaler technique (observed), adherence (prescription refill history), trigger avoidance, and comorbidities (rhinitis, GORD). Poor control is more often due to these factors than to inadequate medication strength.
GINA recommends assessing both symptom control (ACT or GINA criteria) and future risk (exacerbation history, lung function, eosinophils) when making treatment decisions. ACT captures only the symptom control dimension.

✓ when to use

✗ when not to use

clinical pearls

ACT ≥20 = well controlled. This is the number to remember. Below 20, something needs to change — but always check technique and adherence before changing medication.
The ACT is scored 5–25 (not 0–25) because each item scores 1–5, not 0–4. A score of 5 represents the worst possible control across all domains.
A 3-point change is clinically meaningful. When tracking response to treatment changes, look for ≥3-point improvement rather than small fluctuations.
Before stepping up asthma treatment based on a poor ACT score, always check: inhaler technique (observed), adherence (prescription refill history), trigger avoidance, and comorbidities (rhinitis, GORD). Poor control is more often due to these factors than to inadequate medication strength.
GINA recommends assessing both symptom control (ACT or GINA criteria) and future risk (exacerbation history, lung function, eosinophils) when making treatment decisions. ACT captures only the symptom control dimension.

Asthma Control Test (ACT)

questionnaire

✓ when to use

✗ when not to use

clinical pearls

related tools