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Printed on 6/29/2026
For informational purposes only. This is not medical advice.
The ACT is a 5-item patient-completed questionnaire assessing activity limitation, shortness of breath, nighttime symptoms, rescue inhaler use, and self-rated control over the past 4 weeks. Scores ≥20 indicate well-controlled asthma; scores <16 indicate very poorly controlled asthma.
Formula: Sum of 5 items (each 1–5). Total: 5–25. Well controlled ≥20, Not well controlled 16–19, Very poorly controlled ≤15.
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The ACT is completed by the patient (aged ≥12) before or at the start of the clinic visit. Five questions assess: activity limitation from asthma, frequency of shortness of breath, nighttime or early morning awakenings from asthma, rescue inhaler (SABA) use frequency, and the patient's own overall asthma control rating. Each question is scored 1–5, where higher scores indicate better control.
Add the five item scores. Total range is 5 (worst possible) to 25 (best possible). Interpretation: Score 25 = fully controlled; Score 20–24 = well controlled; Score 16–19 = not well controlled (consider step-up therapy); Score ≤15 = very poorly controlled (urgent clinical assessment needed). A change of ≥3 points from a previous visit is the minimal clinically important difference (MCID).
ACT score below 20 should trigger: (1) assessment of inhaler technique (70% of patients use incorrectly); (2) adherence review; (3) trigger identification; (4) spirometry (FEV1/FVC) to objectively confirm obstruction; (5) consideration of FeNO testing for eosinophilic inflammation; (6) biologic therapy screening if ACT <20 with type 2 inflammatory markers. Do not step up therapy based on ACT alone without addressing modifiable factors.
Pulmonologists & Allergists
ACT is administered at every asthma follow-up visit to objectively quantify symptom control over the preceding 4 weeks. Serial ACT scores create a longitudinal record of disease control that supplements spirometry, identifies treatment response or deterioration, and provides patient-reported data for shared decision-making about step-up or step-down therapy. GINA 2024 endorses ACT as the preferred validated patient-reported outcome for asthma monitoring.
Primary Care Physicians & NPs
ACT ≤19 at a follow-up visit is a validated signal to review controller therapy. Before stepping up inhaled corticosteroid (ICS) dose or adding a LABA, address modifiable factors: incorrect inhaler technique (spacer use), poor adherence, ongoing allergen or irritant exposure, and comorbid rhinitis/GERD. ACT improvement of ≥3 points after a therapeutic change confirms clinical response and supports continuation.
Patients & Caregivers
Patients can complete the ACT at home between clinic visits using printed forms or digital apps. A declining home ACT score (even before the next scheduled visit) should prompt the patient to contact their provider before an exacerbation occurs. Asthma action plans linked to ACT thresholds (<20 = yellow zone) provide patients with objective guidance for when to escalate their own treatment.
Allergy/Immunology & Pulmonology Specialists
Biologic therapies for severe asthma (dupilumab, omalizumab, mepolizumab, benralizumab, tezepelumab) typically require ACT <20 as a symptom control criterion alongside type 2 inflammatory biomarkers (blood eosinophils ≥150–300 cells/µL, IgE levels, or FeNO >25 ppb). ACT documentation in the medical record supports insurance authorization and demonstrates medical necessity for high-cost biologics.
Clinical Researchers
ACT is a validated, well-understood patient-reported outcome used in most asthma clinical trials as a primary or secondary endpoint. Its MCID of 3 points is well-established, enabling power calculations and interpretation of trial results. FDA accepts ACT as a patient-reported outcome (PRO) measure for asthma drug applications. The validated Childhood ACT (C-ACT) is used for pediatric trials.
Before escalating pharmacotherapy for an ACT ≤19, systematically assess modifiable factors. Studies show approximately 70% of asthma patients use their inhaler incorrectly. Observe the patient's technique directly or use a validated checklist. Common errors: not exhaling before actuation, too-fast inhalation with MDI, not holding breath for 10 seconds, not shaking MDI, not using spacer with MDI. Correcting technique alone can improve ACT by 3–5 points without changing the prescription.
The pathway to biologic therapy for uncontrolled asthma requires: (1) ACT <20 documenting poor control; (2) blood eosinophils ≥150 cells/µL (dupilumab, mepolizumab, benralizumab) or elevated IgE (omalizumab); (3) adherence and technique confirmed to be adequate; (4) typically 2+ exacerbations requiring OCS in past year or at least 1 hospitalization. FeNO >25 ppb is an additional type 2 biomarker supporting biologic eligibility.
GINA (Global Initiative for Asthma) 2024 guidelines recommend using a validated symptom control tool at every asthma visit. ACT is one of the two endorsed tools (alongside the Asthma Control Questionnaire [ACQ]). Regular ACT administration creates longitudinal data tracking that transforms the clinic visit from a subjective 'How have you been?' conversation to an objective, comparable assessment with benchmarks for action.
The ACT Question 4 (rescue inhaler use) captures frequency, but patients often minimize their SABA use when answering. Ask specifically: 'How many times did you use your rescue inhaler each week on average?' SABA use more than 2 days per week is an independent marker of poor asthma control per GINA guidelines, regardless of the total ACT score. Excessive SABA use is also associated with increased asthma mortality (SMART trial).
Fractional exhaled nitric oxide (FeNO) >25 ppb indicates eosinophilic airway inflammation even when the ACT score appears controlled (20–24). Combined ACT + FeNO monitoring provides a more complete picture of asthma control: FeNO can be persistently elevated during 'silent' airway inflammation that precedes exacerbations. In specialist practice, trending FeNO alongside ACT guides ICS dose titration and biologic eligibility more precisely than ACT alone.
Patients adapt to chronically reduced lung function and may rate their asthma as 'controlled' (ACT 20–24) while spirometry demonstrates significant FEV1 reduction (<70% predicted). This 'patient adaptation phenomenon' means ACT alone should not be used to step down therapy without confirming spirometry. GINA recommends spirometry at diagnosis, after treatment stabilization, and annually in moderate-severe asthma. Do not step down therapy based on high ACT if FEV1 remains significantly below baseline.
Patients frequently underreport nocturnal asthma symptoms, either because they have adapted to waking or because nighttime arousals from cough or wheeze are attributed to other causes. Specifically ask: 'Did asthma wake you up at night, or cause you to cough in the early morning hours?' Many patients answer 'No' to the general question but 'Yes' when asked specifically. Nocturnal asthma is a marker of poor control and often responds to long-acting bronchodilator addition or ICS dose increase.
The original ACT is validated for ages ≥12. The Childhood Asthma Control Test (C-ACT), validated by Liu et al. (J Allergy Clin Immunol 2007), is designed for children aged 4–11 years. C-ACT uses a 7-item questionnaire (4 items by the child using a pictorial scale, 3 items by the caregiver). Score ≤19 indicates poorly controlled childhood asthma. Do not apply the adult ACT to children under 12.
The minimal clinically important difference (MCID) for the ACT is 3 points (Schatz et al., J Allergy Clin Immunol 2009). A change of less than 3 points may represent random variation rather than a true clinical change. Use the MCID when interpreting serial ACT scores in clinical practice and when evaluating treatment response: 'Has this new biologic actually improved ACT by ≥3 points?' If not, reassess the therapy choice.
A common ACT scoring phenomenon is the 'halo effect' — patients rate Question 5 (overall asthma control) as 4 or 5 (well/completely controlled), while Questions 1–4 (activity, dyspnea, nights, SABA) score 2–3. This can artificially inflate the total score. Review each item individually with the patient to ensure the total score reflects actual symptoms. Clinical systems that flag Q5 ratings inconsistent with Q1–4 responses can identify this pattern.
ACT developed by Nathan et al. (J Allergy Clin Immunol 2004). Validated against specialist-defined asthma control: sensitivity 71%, specificity 71% for not-well-controlled at cutoff ≤19. MCID of 3 points: Schatz et al. (J Allergy Clin Immunol 2009). GINA 2024 endorses ACT as a validated patient-reported outcome for asthma symptom control. Biological therapy eligibility integrating ACT reviewed in Israel et al. (JAMA 2021). Childhood ACT validated by Liu et al. (J Allergy Clin Immunol 2007).
Your Asthma Control Test (ACT) score reflects how well your asthma has been controlled over the past 4 weeks. A score of 20–25 indicates well-controlled asthma, meaning your current treatment regimen is working effectively and you are experiencing minimal symptoms, few activity limitations, and little need for rescue medications. A score of 16–19 indicates not well-controlled asthma, suggesting your treatment may need to be stepped up or adherence and inhaler technique reassessed. A score of 15 or below indicates very poorly controlled asthma, which warrants urgent clinical evaluation and likely a significant change in management.
A change of 3 or more points on the ACT is considered the minimal clinically important difference (MCID), meaning it represents a real and meaningful change in asthma control rather than random variation. Tracking your score over time helps identify trends and the impact of treatment adjustments.
Use the ACT at every asthma follow-up visit, typically every 1–6 months, as recommended by GINA (Global Initiative for Asthma) and NAEPP (National Asthma Education and Prevention Program) guidelines. It serves as a standardized, patient-reported measure that helps clinicians make step-up or step-down therapy decisions based on recent symptom control rather than relying solely on spirometry or clinical impression.
The ACT is also valuable for patient self-monitoring between clinic visits. Patients who notice a declining score can seek medical attention before a serious exacerbation occurs. It is validated for use in adults and adolescents aged 12 and older; the Childhood ACT (C-ACT) is available for children aged 4–11.
The ACT is a patient-reported outcome measure and is subject to recall bias and subjective interpretation of symptom severity. Patients may overestimate or underestimate their level of control depending on their expectations, health literacy, and tolerance of symptoms. It does not replace objective measures of lung function such as spirometry (FEV1) or peak expiratory flow, which may reveal airflow obstruction even when symptoms are perceived as well-controlled.
The ACT does not assess exacerbation risk factors such as blood eosinophil count, FeNO levels, allergen exposure, medication adherence, or inhaler technique. A patient can have a well-controlled ACT score yet remain at high risk for future exacerbations due to persistent airway inflammation. Additionally, the ACT was validated for chronic persistent asthma and may not accurately reflect control in patients with intermittent asthma, exercise-induced bronchoconstriction, or occupational asthma.
For related assessments, see COPD GOLD, P/F Ratio and FiO₂ Conversion.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
April 21, 2026 · trust-baseline
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