• There is no single diagnostic test for chronic obstructive pulmonary disease (COPD).
• Make a diagnosis of COPD if the person meets all of the following criteria:
• Age older than 35 years.
• Presence of a risk factor (for example smoking, history of smoking, or an occupational exposure).
• Typical symptoms.
• Absence of clinical features of asthma.
• Presence of airflow obstruction confirmed by post-bronchodilator spirometry.
• Individual physical signs are not diagnostic of COPD, and in some people there may be no abnormal physical signs.
• Consider alternative diagnoses.
• Consider the possibility of alpha₁-antitrypsin deficiency if the person is younger than 40 years of age or has a family history of alpha₁-antitrypsin deficiency.
• If suspected, refer the person to a respiratory specialist for investigations and treatment.
• Reconsider the diagnosis of COPD (and consider the possibility of asthma) if the person has a marked response to drug treatment, illustrated by either:
• A marked improvement in symptoms, or
• Return of forced expiratory volume in 1 second (FEV₁) and FEV₁/FVC (forced vital capacity) ratio to normal.

These recommendations are based on the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• Typical symptoms of chronic obstructive pulmonary disease include:
• Exertional breathlessness.
• Chronic cough.
• Regular sputum production.
• Frequent 'winter bronchitis'.
• Wheeze.
• Other symptoms that may be present include:
• Weight loss.
• Exercise intolerance.
• Ankle swelling.
• Fatigue.
• Chest pain or haemoptysis. These are uncommon, and their presence may indicate an alternative or concomitant diagnosis. For more information, see Differential diagnosis.

These recommendations are based on expert opinion in the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• The following signs may be present:
• Hyperinflated chest.
• Wheeze or quiet breath sounds.
• Pursed lip breathing.
• Use of accessory muscles.
• Peripheral oedema.
• Cyanosis.
• Raised jugular venous pressure.
• Cachexia.

This information is based on expert opinion in the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• Ensure that there is access to spirometry performed by an appropriately trained professional and supported by quality-control processes, and that the skills are available to interpret results.
• Referral to a community or hospital spirometry service may be necessary.
• Measure post-bronchodilator spirometry to confirm the diagnosis of chronic obstructive pulmonary disease (COPD).
• Do spirometry 15–20 minutes after the person has inhaled salbutamol 200 micrograms delivered via a spacer device (terbutaline 500 micrograms may be an alternative). If ipratropium bromide is used, wait for 30 minutes before doing spirometry.
• In COPD, the ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC ratio) is less than 0.7.
• Predicted normal values of FEV₁ and FVC depend on age, height, and sex. These values may over diagnose COPD in elderly people and are not applicable in black and Asian populations.
• The slow or relaxed vital capacity (SVC) may be used instead of FVC to calculate the ratio if either the SVC is higher than the FVC, or the person cannot perform a forced manoeuvre to full exhalation.
• If the FEV₁ is 80% predicted normal or greater, a diagnosis of COPD should be made only in the presence of respiratory symptoms, for example breathlessness or cough.
• Assess the severity of airflow obstruction according to the reduction in FEV₁ — see Assessment of severity.
• Routine spirometric reversibility testing is not recommended unless COPD and asthma cannot be distinguished clinically (see Distinguishing COPD and asthma).
• Repeat spirometry if the person has an exceptionally good response to treatment; reconsider the diagnosis if the FEV₁/FVC ratio is 0.7 or greater at follow up.

These recommendations are mainly based on the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• The statement that referral to a community or hospital spirometry service may be necessary is based on expert opinion and evidence of low-quality delivery and interpretation of spirometry in primary care, discussed in guidelines on diagnostic spirometry in primary care by the GP Airways Group [Levy et al, 2009].
• The recommendation that spirometry should be post-bronchodilator is new in the updated 2010 NICE guideline. This recommendation by NICE is based on limited evidence from a cross-sectional study and a case series study of increased diagnostic accuracy compared with pre-bronchodilator spirometry, and on the consensus of the guideline development group. The major limitation of the evidence is the lack of a gold (reference) standard for chronic obstructive pulmonary disease (COPD).
• The recommendations on the choice, dose, and delivery of bronchodilator, and how long after inhalation spirometry should be done, are based on expert opinion from CKS reviewers and on extrapolations from recommendations in guidelines on diagnostic spirometry in primary care by the GP Airways Group on how to do reversibility testing using a short-acting bronchodilator [Levy et al, 2009].
• The statement that a slow or relaxed vital capacity (SVC) may be used instead of forced vital capacity (FVC) to calculate the ratio if either the SVC is higher than the FVC, or the person cannot perform a forced manoeuvre to full exhalation, is derived from guidelines on diagnostic spirometry in primary care by the GP Airways Group [Levy et al, 2009] and a consensus statement in the NICE COPD guideline [National Clinical Guideline Centre, 2010].
• Routine spirometric reversibility testing is not recommended by NICE on the basis of evidence from mainly observational studies and one randomized controlled trial indicating that:
• Repeated measurements of the forced expiratory volume in 1 second (FEV₁) can show small spontaneous fluctuations.
• The results of a reversibility test performed on different occasions can be inconsistent and not reproducible.
• Over reliance on a single reversibility test may be misleading unless the change in FEV₁ is greater than 400 mL.
• Response to long-term therapy is not predicted by acute reversibility testing.
• Other recommendations by NICE are based on expert opinion or extrapolations from higher levels of evidence.

• The differential diagnosis of chronic obstructive pulmonary disease (COPD) includes any condition that presents with breathlessness and/or cough. For example:
• Asthma — consider if the person has a family history, has other atopic diseases or nocturnal or variable symptoms, is a non-smoker, or experienced onset of symptoms at younger than 35 years of age. For more information, see Distinguishing COPD and asthma and the CKS topic on Asthma.
• Bronchiectasis — clinical features include copious sputum, frequent chest infections, a history of childhood pneumonia, and coarse lung crepitations.
• Congestive cardiac failure — clinical features include breathlessness when lying flat, a history of ischaemic heart disease, and fine lung crepitations. See the CKS topic on Heart failure - chronic.
• Lung cancer — consider if the person has haemoptysis, weight loss, or hoarseness. See the CKS topic on Lung cancer - suspected.
• Interstitial lung disease (asbestosis, pneumoconiosis, fibrosing alveolitis, sarcoidosis) — clinical features include dry cough and fine crepitations.
• Bronchopulmonary dysplasia — consider in a young adult with recurrent chest infections.
• Anaemia. See the CKS topics on Anaemia - iron deficiency and Anaemia - B12 and folate deficiency.
• Obstructive sleep apnoea. See the CKS topic on Sleep apnoea.
• Tuberculosis. See the CKS topic on Tuberculosis.
• These conditions may be present in addition to COPD.
• For detailed information on the differential diagnosis of people with cough or breathlessness, see the CKS topics on Cough and Breathlessness.

This information is derived from the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010], the Global strategy for diagnosis, management, and prevention of COPD [GOLD, 2009], a guideline on interstitial lung disease from the British Thoracic Society in collaboration with the Thoracic Society of Australia and New Zealand and the Irish Thoracic Society [Bradley et al, 2008], and a study of the validity of primary care diagnosis of COPD [Sichletidis et al, 2007].

• Chronic obstructive pulmonary disease (COPD) and asthma can be difficult to distinguish and may coexist.
• Compare clinical features.
• If diagnostic doubt remains, one or more of the following strategies are recommended:
• Do longitudinal observations of symptoms, peak flow, and/or spirometry.
• Serial domiciliary peak expiratory flow measurements showing 20% or greater diurnal or day-to-day variability indicate asthma. Peak expiratory flow is not routinely recommended for the diagnosis or assessment of people with COPD, as it may significantly underestimate the degree of airflow obstruction, but it may help to distinguish COPD from asthma.
• On spirometry, clinically significant COPD is not present if the ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC ratio) increases to 0.7 or greater at follow up. Suspect asthma, in which airways obstruction is variable.
• Perform reversibility testing using either inhaled bronchodilators or oral prednisolone. The following findings identify asthma:
• A large (greater than 400 mL FEV₁) response to inhaled bronchodilators.
• A large (greater than 400 mL FEV₁) response to 30 mg oral prednisolone given daily for 2 weeks.
• Start drug treatment and arrange early follow up that includes repeat spirometry. Reconsider the diagnosis of COPD (and suspect asthma) if the person has a marked response to drug treatment, illustrated by either:
• A marked improvement in symptoms, or
• Return of FEV₁ and the FEV₁/FVC ratio to normal.
• Refer the person to a respiratory specialist for more detailed investigations.

These recommendations are based on expert opinion in the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• Arrange a chest X-ray for all people with suspected chronic obstructive pulmonary disease to exclude other pathologies (see Differential diagnosis).

This recommendation is based on expert opinion in the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].

• Drug treatment can be started before the diagnosis has been confirmed, provided that spirometry has been performed and other assessments to exclude asthma have been undertaken.

These recommendations are based on the National Institute for Health and Clinical Excellence (NICE) clinical guideline Management of chronic obstructive pulmonary disease in adults in primary and secondary care (partial update) [National Clinical Guideline Centre, 2010; NICE, 2010].