The Chest Clinic
Investigations
Tests help us understand the cause of symptoms, confirm or monitor a diagnosis and plan treatment. Your consultant selects the investigations that answer your particular clinical questions. Some are performed by our respiratory physiology team; others are arranged through the relevant hospital or specialist service. Availability varies by location.
Symptoms | Conditions and treatments | Meet our physiologists | Appointments
CPEX: cardiopulmonary exercise testing (CPET)
CPEX is a major part of Dr Matthew Knight's private practice at The Chest Clinic. Also called CPET, it examines how the lungs, heart and muscles work together during exercise. It can be particularly useful when breathlessness or reduced exercise tolerance remains unexplained after initial investigations, and in selected assessments before surgery.
You usually exercise on a stationary bicycle while wearing a mask or mouthpiece. The workload increases gradually, with breathing, oxygen uptake, carbon dioxide output, heart rhythm, blood pressure and oxygen saturation monitored. The team assesses your suitability beforehand and supervises the test and recovery.
The results help identify what limits exercise and guide further investigation, treatment or rehabilitation. They are interpreted alongside your symptoms and other tests; CPEX does not diagnose every cause of fatigue or breathlessness on its own.
Wear comfortable exercise clothing and suitable footwear. Follow your appointment instructions about food, caffeine, activity and medicines; do not stop treatment unless advised. Tell the team about recent illness or mobility difficulties.
Ask about CPEX assessment | NHS: cardiopulmonary exercise testing
Full lung function testing
Spirometry measures how much air you can breathe out and how quickly. You breathe through a mouthpiece while a physiologist coaches you through repeated attempts to obtain reliable measurements. It helps assess airflow obstruction and other patterns, but results must be interpreted with your history and other findings.
Lung volumes and body plethysmography assess the amount of air in your lungs, including air remaining after breathing out. For body plethysmography, you sit in a transparent booth and perform breathing manoeuvres through a mouthpiece. Let the team know if enclosed spaces make you uncomfortable.
Gas transfer (TLCO or DLCO) assesses how effectively gas passes from the lungs into the blood. It involves breathing a small test-gas mixture and briefly holding your breath. This provides information beyond spirometry alone.
The Chest Clinic uses the Geratherm Respiratory Bodystik, supplied by Love Medical, for full body plethysmography, with a compatible diffusion module for gas-transfer testing. Your appointment is tailored to the measurements requested.
Wear comfortable clothing and follow your appointment instructions. Tell the team about recent illness and any concerns about performing the test. Only withhold inhalers if your clinical team has specifically asked you to do so.
NHS: full lung function tests | NHS: spirometry | Geratherm equipment information
Bronchodilator reversibility
Spirometry is repeated after an inhaled medicine that opens the airways. A significant improvement can support an asthma diagnosis in the right setting. A result without a significant change does not, by itself, exclude asthma. Tell the team which inhalers you use and when you last took them.
FeNO: a test of airway inflammation
Fractional exhaled nitric oxide (FeNO) measures nitric oxide in your breath, providing information about a type of airway inflammation often associated with asthma. You breathe steadily into a device while being guided by the team. It measures something different from airflow testing. Inhaled steroids can lower the result, so a low FeNO does not necessarily exclude asthma.
NHS: FeNO explained | BTS/NICE/SIGN asthma testing guidance
Peak-flow monitoring and airway challenge tests
A peak-flow diary can show how airflow varies over time. We explain the technique, recording schedule and how to keep track of symptoms and medicines. Do not alter treatment solely in response to a reading unless this is part of your agreed action plan.
If asthma remains suspected despite inconclusive initial tests, a specialist airway challenge test may be considered. Tests such as methacholine or mannitol challenge assess airway responsiveness under supervision with repeated breathing measurements. They can temporarily cause cough or chest tightness, so suitability and preparation are assessed carefully. Specialist tests are arranged where clinically appropriate and available.
Allergy testing
Skin-prick testing can help assess whether allergens contribute to nasal or asthma symptoms. Small drops of selected allergen solutions are placed on the skin and the surface is pricked. The team checks for a local reaction, which may be itchy. Blood tests for specific IgE are an alternative or additional investigation in selected situations.
A positive result indicates sensitisation, not necessarily a clinically important allergy; it must fit your symptoms and exposures. These are not general tests for food intolerance. Antihistamines can interfere with skin testing: follow individual instructions about whether and when to withhold them, and tell the team about previous severe reactions and your medicines.
Home sleep studies
We use BRAEBON MediByte and MediByte Junior equipment to investigate sleep-related breathing problems. The team shows you how to fit the recorder and sensors, use them overnight and return the equipment. Signals recorded vary by the device and setup and may include breathing, oxygen levels, pulse and body position.
Home respiratory polygraphy helps identify obstructive sleep apnoea and assess its severity. It is different from a full laboratory sleep study. If the recording is inadequate, or a negative result does not explain continuing symptoms, further testing may be needed. Overnight oximetry measures oxygen levels but does not answer every question about sleep or breathing.
If CPAP is needed, most patients transfer to NHS care. Their GP usually refers them to their local NHS sleep clinic; our assessment and test results can support that referral. The NHS sleep team confirms treatment and arranges equipment and follow-up.
NICE: sleep investigations and treatment | BRAEBON device information | Sleep apnoea guide
Oxygen assessment and walking tests
Pulse oximetry estimates oxygen saturation using a sensor, usually on a finger. Blood-gas testing may be needed to measure oxygen and carbon dioxide more directly. Supervised walking tests assess exercise capacity and whether oxygen levels fall with exertion. Oxygen prescriptions require clinical assessment; a single home oximeter reading is not a treatment plan.
Blood tests, sputum and other samples
Tests are chosen to answer specific questions. Blood tests may assess anaemia, infection, eosinophils, allergy, immune function or autoimmune disease. Sputum cultures can identify organisms and guide antibiotics; selected samples are tested for TB or non-tuberculous mycobacteria. Sampling instructions matter, and a result may need interpretation alongside symptoms, imaging and repeat samples.
Chest imaging and heart investigations
Chest X-ray provides an initial overview in many clinical situations. CT provides more detailed images; high-resolution CT is used for conditions such as ILD and bronchiectasis. CT pulmonary angiography is one test used when pulmonary embolism is suspected. Contrast use, radiation and any relevant risks are discussed for the proposed scan.
Thoracic ultrasound helps assess fluid around the lung and guide pleural procedures. PET-CT can help characterise or stage selected suspected cancers but does not replace tissue diagnosis in every case. Comparison with previous imaging is often valuable.
ECG, echocardiography and selected cardiac blood tests may be arranged when heart disease could contribute to breathlessness or chest symptoms. Results guide whether cardiology or other specialist assessment is needed.
Bronchoscopy
A flexible camera is passed through the mouth or nose into the breathing passages to inspect the airways and obtain samples where needed. Samples may include washings, brushings or biopsies. Bronchoscopy can investigate selected scan abnormalities, bleeding, infection or suspected cancer; it is not a routine test for every cough.
EBUS and EUS-guided sampling
Endobronchial ultrasound (EBUS) combines a bronchoscope with ultrasound to locate lymph nodes or other structures next to the airways. A fine needle can collect samples for diagnosis and, when relevant, cancer staging.
Endoscopic ultrasound (EUS) examines structures from the oesophagus. EUS-B uses an ultrasound bronchoscope through the oesophagus in selected cases. These approaches may complement EBUS; the route depends on the target and clinical question. A sample does not always provide a conclusive diagnosis, and further investigation is sometimes needed.
Robotic bronchoscopy and other lung biopsies
Robotic-assisted bronchoscopy can help a specialist reach selected small or peripheral lung abnormalities using CT-based planning and navigational guidance. The clinical team remains in control. Suitability depends on the target, your health and local expertise, and the procedure is not available at every hospital.
Other options include CT-guided needle biopsy through the chest wall, pleural biopsy or surgical biopsy. The multidisciplinary team recommends an approach based on the safest useful sample. The risks and alternatives differ, and a biopsy may not always give a definitive answer.
Sedation and preparation for bronchoscopic procedures
Our bronchoscopic investigations are usually undertaken with deep sedation supported by an anaesthetist; some procedures require general anaesthesia. Your team will explain the plan for your procedure. This is separate from local anaesthetic used to numb the airway or procedure site.
Follow the hospital's fasting and medication instructions, including specific advice about blood thinners and diabetes treatment. Do not stop medicines on your own. Discuss allergies, previous anaesthetic problems and relevant health conditions. You will usually need an adult to take you home and follow the hospital's restrictions on driving and other activities after sedation.
Consent includes discussion of bleeding, infection, low oxygen levels and, for relevant biopsies, pneumothorax, as well as the possibility of an inconclusive result. The team will explain recovery, warning symptoms and how to obtain help after discharge.
BTS procedure and clinical resources | Our diagnostic and multidisciplinary cancer pathway
Pleural aspiration, drainage and biopsy
If fluid has collected around a lung, ultrasound helps identify a safe site for sampling or drainage. After local anaesthetic, a needle or small tube is introduced between the ribs. Fluid can be tested for its cause and sometimes removed to relieve breathlessness. Selected patients need a chest drain, pleural biopsy or thoracoscopy through a specialist service.
Your team explains the purpose, alternatives and risks, including pain, bleeding, infection and pneumothorax. Preparation and aftercare depend on the procedure and your medicines.
NHS: pleural aspiration | Pleural effusion guide
Results and the next steps
Before testing, we explain why the investigation is recommended and what it could change. The clinical team interprets the results together, discusses any remaining uncertainty and agrees treatment or follow-up. Bring previous scans, reports and an up-to-date medicines list where available, and ask when and how you will receive your results.
For inhalers, biologics, cough therapy, gefapixant, CPAP, rehabilitation and other treatment options, see our Conditions page and Symptoms page.
General information for adults. Your appointment letter and clinical team's instructions take priority over general preparation advice.