How is COPD or emphysema diagnosed by a GP or specialist? 

The diagnosis of COPD or emphysema typically begins with a GP review of your symptoms and medical history, followed by a breathing test called spirometry, which is the gold standard for identifying airflow obstruction. If the initial tests suggest a lung condition, a GP may refer you to a respiratory specialist for further investigation, such as a high-resolution CT scan to look for structural damage to the air sacs ‘emphysema’ or blood tests to check for genetic predispositions. 

What We will cover in this Article 

• The initial clinical assessment and symptom review by a GP. 

• Understanding spirometry: the primary diagnostic tool for COPD. 

• The role of chest X   rays and CT scans in identifying lung damage. 

• Additional diagnostic tests, including peak flow and blood gases. 

• How specialists differentiate COPD from asthma or other conditions. 

• Screening for Alpha   1 antitrypsin deficiency in the UK. 

The Initial GP Assessment 

When you visit a GP with concerns about breathlessness or a chronic cough, the first step is a detailed discussion about your history. The GP will look for specific ‘risk factors’, such as a long-term history of smoking or exposure to occupational dust and fumes. They will also ask about the frequency of your symptoms and whether they are worsening over time. 

During the physical examination, the GP will listen to your chest with a stethoscope to check for wheezing or ‘quiet’ breath sounds, which can be signs of hyperinflated lungs. They may also check your ‘sats’ ‘oxygen saturation levels’ using a small device on your finger. However, because physical signs can be subtle in the early stages, further objective testing is always required for a formal diagnosis. 

Spirometry: The Essential Breathing Test 

Spirometry is the most important test for diagnosing COPD. It measures how much air you can breathe out and how quickly you can do it. You will be asked to take a deep breath and blow as hard and fast as you can into a machine called a spirometer. 

The test focuses on two key measurements: 

1. FEV1: The volume of air you can blow out in the first second of a forceful exhale. 

2. FVC: The total amount of air you can blow out in one complete breath. 

If the ratio between these two numbers is lower than a certain threshold ‘usually less than 70%’, it indicates that your airways are obstructed. In the UK, you may be given a ‘reversibility test’, where you use an inhaler and repeat the test 15 minutes later to see if the obstruction is temporary ‘like asthma’ or permanent ‘like COPD’. 

Test Result	Indication	Clinical Significance
Normal Ratio	Healthy Lung Function	Airflow is not obstructed.
Low Ratio	Airflow Obstruction	Suggestive of COPD or chronic bronchitis.
No Improvement after Inhaler	Irreversible Obstruction	Supports a diagnosis of COPD over asthma.

Specialist Imaging and Advanced Testing 

While a GP can often diagnose COPD using spirometry, a respiratory specialist may perform more detailed tests to understand the ‘phenotype’ of your condition   specifically whether emphysema or chronic bronchitis is dominant. 

• Chest X   ray: This is often used to rule out other conditions like lung cancer or heart failure. In advanced emphysema, it may show ‘hyperinflation’, where the lungs appear larger and the diaphragm looks flattened. 

• CT Scan: A high-resolution CT scan is the best way to see the physical destruction of the air sacs. It can identify emphysema even before it shows up on a breathing test. 

• Blood Tests: Specialists often perform a blood test to check for Alpha   1 antitrypsin deficiency, particularly in younger patients or non-smokers. 

• FeNO Test: This measures inflammation in the airways to help rule out asthma as the primary cause of your symptoms. 

‘A specialist diagnosis often involves a combination of functional data from breathing tests and structural data from imaging to create a complete picture of the patient’s lung health.’ 

To Summarise 

Diagnosing COPD or emphysema is a multi   step process that moves from a GP symptom review to objective breathing tests and specialized imaging. Spirometry remains the primary tool for confirming airflow obstruction, while CT scans and blood tests allow specialists to identify the specific type of lung damage present. Early and accurate diagnosis is essential for starting the correct treatment plan and slowing the progression of the disease. 

If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot 

This article provides medically neutral information regarding the diagnostic pathways for chronic respiratory conditions in the UK. 

• Reviewer: Dr. Stefan Petrov. Dr. Petrov is a UK   trained physician with an MBBS and postgraduate certifications in BLS and ACLS. He has hands   on experience in general medicine, surgery, anaesthesia, and emergency care. He has worked in hospital wards and intensive care units, performing diagnostic procedures and contributing to patient   focused health content. 

• Clinical Standards: This content is written to reflect the 2026 UK clinical frameworks and protocols for the diagnosis of chronic obstructive pulmonary disease. 

• Accuracy Note: This information is for general awareness and does not replace a professional clinical diagnosis or the need for a formal lung function assessment by a qualified practitioner.