Understanding COPD: Symptoms & Diagnosis

Written & reviewed by the BestDoctors.sg editorial team · Last updated 29 Aug 2026 · General information, not medical advice

Why COPD is easy to miss

COPD often develops slowly, and its early symptoms are easy to explain away – a cough put down to smoking, breathlessness put down to age or being unfit. This is exactly why it is frequently diagnosed late, after more lung damage than necessary has occurred. So the practical message is: if you are older, or a current or former smoker, and you have a persistent cough, breathlessness, or frequent chest infections, it is worth getting checked rather than shrugging it off. Recognising the symptoms for what they might be, and acting on them, is the first step to earlier treatment and less avoidable harm.

The symptoms of COPD

The core symptoms are breathlessness, at first on exertion – stairs, hills, hurrying – and gradually worsening over time; a persistent, chronic cough, often bringing up phlegm (sputum); frequent chest infections, which also take longer to clear; wheezing; and tiredness. Symptoms tend to fluctuate and worsen slowly, punctuated by flare-ups when they get suddenly worse. In more advanced COPD, some people notice unintended weight loss, more marked fatigue, or swollen ankles. Understanding this pattern helps you describe your experience clearly and notice changes that matter.

What COPD is

To make sense of the symptoms, it helps to know what COPD is: an umbrella term – covering chronic bronchitis and emphysema – for long-term conditions where the airways are narrowed and airflow out of the lungs is obstructed. It is long-term, slowly progressive, and not fully reversible, which distinguishes it from asthma, where the obstruction is largely reversible. Some people have features of both, which a doctor can sort out. Knowing this explains why breathlessness worsens gradually, why phlegm and cough are common, and why the aim of treatment is to control symptoms and slow progression rather than cure.

Spirometry: the key test

COPD is diagnosed from your symptoms and history – especially smoking or exposure to fumes and dust – plus a breathing test. The central, confirming test is spirometry: you breathe into a machine that measures how much air you can blow out and how fast, often before and after an inhaled medicine. Spirometry confirms the airflow obstruction and helps distinguish COPD from asthma – it is the test that clinches the diagnosis. It is simple and painless. The site’s lung-function-tests (spirometry) guide explains the test itself in more detail if you would like to know what to expect.

Other tests

Spirometry makes the diagnosis, but other tests are sometimes used to rule out other causes or assess how things stand. A chest X-ray can look for infection, lung cancer or other causes of your symptoms; a CT scan gives more detailed lung images; blood tests can check for anaemia or, occasionally, the genetic alpha-1 antitrypsin deficiency; and a blood-oxygen check (a painless sensor on the finger) measures your oxygen level. These are used selectively rather than to diagnose COPD on their own. Importantly, coughing up blood or unexplained weight loss usually point elsewhere and should be assessed in their own right.

Who diagnoses and treats COPD

In Singapore, your GP or polyclinic is usually the first stop: they recognise the symptoms, take your history, and can arrange breathing tests or refer you. A respiratory (lung) physician often confirms the diagnosis with spirometry and guides specialist care, including inhaler decisions and referral to pulmonary rehabilitation. The site’s directory of respiratory physicians can help you find one. Getting a clear diagnosis is a positive step, not a verdict – it means the cause of your symptoms is identified and effective treatment, which controls symptoms and slows progression, can begin.

Getting checked early

Because earlier diagnosis leads to earlier treatment and less avoidable lung damage, it is worth acting on persistent symptoms rather than waiting. Alongside diagnosis, the single most valuable step is stopping smoking, which slows the disease at any stage – support is available through your GP, pharmacists and the HPB QuitLine (1800-438-2000). Vaccinations against flu, pneumococcal infection and COVID help prevent the chest infections that worsen COPD. Treat the diagnosis as the start of taking control, with a team and proven treatments behind you, rather than as bad news to be feared.

When to seek help

If your symptoms suddenly worsen – more breathlessness or cough, or more or discoloured phlegm – that is a flare-up: act on your plan and contact your team, as the flare-up guide explains. Call 995 for severe breathlessness that does not ease or leaves you unable to speak in full sentences, blue or grey lips or fingers, drowsiness or confusion, chest pain, or coughing up blood. And, as above, have coughing up blood or unexplained weight loss assessed separately rather than assuming it is the COPD. Knowing these thresholds helps you respond calmly and appropriately to changes.

Related COPD topics

• Living with COPD
• Inhalers & medication
• Managing breathlessness
• Recognising a flare-up
• Staying active
• COPD & mental health
• Eating well
• Stopping smoking with COPD
• Work, travel & daily life
• COPD overview
• Pulmonary rehabilitation
• Living with home oxygen
• Respiratory physicians in Singapore

Sources

• NHS – COPD symptoms: nhs.uk
• NHS – COPD diagnosis: nhs.uk
• NHS – COPD causes: nhs.uk
• NHS – COPD: nhs.uk