B. FEV1/FVC < 70% + symptoms suggestive of COPD - Explanation
Please see the 2010 NICE guidelines for further details. Patients can now be diagnosed with ‘mild’
COPD if their FEV1 predicted is > 80% if they have symptoms suggestive of COPD.
COPD: investigation and diagnosis
NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are
smokers or exsmokersand have symptoms such as exertional breathlessness, chronic cough or
regular sputum production.
The following investigations are recommended in patients with suspected COPD:
- post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
- chest x-ray: hyperinflation, bullae, flat hemidiaphragm. Also important to exclude lung cancer
- full blood count: exclude secondary polycythaemia
- body mass index (BMI) calculation
The severity of COPD is categorised using the FEV1*:
| Post-bronchodilator FEV1/FVC | FEV1 (of predicted) | Severity |
| < 0.7 | > 80% | Stage 1 – Mild** |
| < 0.7 | 50-79% | Stage 2 – Moderate |
| < 0.7 | 30-49% | Stage 3 – Severe |
| < 0.7 | < 30% | Stage 4 – Very severe |
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of
airflow obstruction.
*note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is
greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as
Stage 1 – mild
**symptoms should be present to diagnose COPD in these patients
