COPD Assessment Test (CAT Score)

How the COPD Assessment Test Measures Symptom Impact

The COPD Assessment Test (CAT) is a short, patient-completed questionnaire that quantifies how much COPD affects a person's daily life. It covers eight domains — cough, phlegm, chest tightness, breathlessness on exertion, activity limitation at home, confidence leaving home, sleep, and energy. Each item is scored from 0 (no impact) to 5 (maximum impact), and the eight scores are added to give a total between 0 and 40.

The total score is grouped into four bands that describe the overall impact of the disease. A score of 0–10 indicates low impact, 11–20 medium impact, 21–30 high impact, and 31–40 very high impact. Higher scores are associated with worse health status, more symptoms, and a greater burden of disease, and the CAT is widely used both to assess baseline impact and to monitor change over time.

Using the CAT in Clinical Practice

The CAT is a core component of the GOLD assessment of symptom burden: a CAT score of 10 or more indicates high symptom burden and helps assign a patient to Group B or E in the GOLD ABE classification. A change of at least 2 points is generally considered a clinically meaningful difference, so the CAT is useful for tracking response to treatment and rehabilitation. Because it is patient-reported, the CAT complements — but does not replace — objective measures such as spirometry.

Clinical Caveats

The CAT reflects the patient's perception of their symptoms and should be interpreted in the context of the full clinical picture, including exacerbation history, spirometry, and functional status. It is not a diagnostic tool and does not measure lung function directly. Scores can be influenced by factors other than COPD, such as concurrent anxiety, depression, or other chronic conditions, so always consider the whole patient when interpreting the result.