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Lung function tests before surgery | CION Cancer Clinics
A lung function test before surgery, also called a pulmonary function test, measures how much air you can breathe out and how quickly. It shows whether your lungs have enough reserve to recover after an operation, especially on the chest or upper abdomen. Most results lead to preparation, such as inhalers and breathing exercises, rather than a refusal. This page explains the test and your report. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
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Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed September 2026, next review due September 2027
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On this page
- What does a lung function test before surgery show?
- Which breathing tests might you be asked to do?
- What happens during spirometry?
- What do the words on a lung function report mean?
- How can the results change your surgery plan?
- How should you prepare for a lung function test?
- What do people often get wrong about breathing tests?
- Common questions about lung function tests before surgery
The short answer
What does a lung function test before surgery show?
A lung function test, also called a pulmonary function test or PFT, measures how much air you can breathe out and how fast. It shows whether your lungs have enough reserve to recover well after an operation.
Why breathing matters after surgery
After an operation on the chest or upper abdomen, deep breaths and a strong cough hurt, so people breathe shallowly. Mucus collects and chest infections follow more easily. Lungs that start with less reserve are more likely to struggle. The test helps the team see this in advance and prepare you for it.
Who is usually asked to have one
People having lung surgery almost always need one, because part of the lung is being removed. It is also common before operations on the food pipe, stomach or liver, and for anyone with COPD, asthma, a long smoking history or breathlessness on walking. Many people having smaller operations elsewhere do not need it.
What this page cannot tell you
It cannot tell you whether your numbers are good enough for your operation. That depends on the surgery planned, your other tests and how you manage in daily life.
What your family can watch for at home
Everyday clues matter as much as the numbers. Can your parent climb a flight of stairs without stopping? Do they get breathless while bathing or talking? Do they cough up mucus every morning? Tell the team what you see. These details help them read the test result for the person in front of them.
The tests in the family
Which breathing tests might you be asked to do?
Spirometry is the most common. The others are added when the team needs more detail.
Spirometry
You blow as hard and fast as you can into a tube. It measures how much air your lungs hold and how quickly you can empty them.
Gas transfer (DLCO)
You breathe in a harmless gas mix and hold your breath briefly. It shows how well oxygen passes from the lungs into the blood.
Often asked before
- Lung surgery
- Surgery after chest radiotherapy
Oxygen level checks
A clip on the finger reads oxygen levels. Sometimes a blood sample from the wrist artery gives a more exact reading.
Walking or stair tests
How far you walk, or how many stairs you climb, while oxygen is watched. Simple, and very telling about real-life reserve.
Exercise testing (CPET)
You pedal a bicycle while breathing and heart signals are recorded. It is used in some centres for borderline cases.
Not sure whether this applies to you?
Ask an oncologistOn the day
What happens during spirometry?
Getting ready
Your height and weight are measured, because the results are compared with what is expected for someone of your age, size and sex. You sit upright in a chair.
The clip and the mouthpiece
A soft clip closes your nose so that all the air goes through the mouthpiece. You seal your lips firmly around it.
The big breath out
You breathe in as deeply as you can, then blow out as hard and as long as possible. The technician will encourage you loudly. That is normal.
Repeats and the inhaler
The blow is repeated a few times for a reliable reading. You may be given an inhaler and tested again to see if your airways open up.
On your report
What do the words on a lung function report mean?
- FEV1
- How much air you blow out in the first second. It is one of the main numbers surgeons look at.
- FVC
- The total amount of air you can blow out after the deepest breath in.
- FEV1/FVC ratio
- Compares the two. A low ratio suggests narrowed airways, as in COPD or asthma.
- Percent predicted
- Your result compared with an average person of your age, height and sex.
- Obstructive or restrictive pattern
- Obstructive means air struggles to get out. Restrictive means the lungs cannot fill fully.
- Post-bronchodilator
- The result after using an inhaler that opens the airways.
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After the results
How can the results change your surgery plan?
Most people's results lead to preparation, not refusal. The team uses them to decide how to protect your breathing before and after the operation.
Preparing the lungs
You may be given inhalers, taught breathing exercises and asked to walk more each day. Stopping smoking, even a short while before surgery, helps. A chest infection is treated first.
Before lung surgery
The surgeon estimates how much breathing capacity will be left once part of the lung is removed. Poor results may lead to a smaller operation, more tests or a discussion about treatment without surgery.
Who the test may not suit
Hard blowing is not advised soon after a heart attack, eye surgery, a collapsed lung or a large hernia repair, or with chest pain or coughing up blood. Tell the technician. Other tests can be used instead.
Questions worth asking
Do my results change the operation, or only how I am prepared? Should I use an inhaler every day before surgery? Will a physiotherapist teach me breathing exercises? Will the test be repeated before the date? Write the answers down so the whole family follows the same plan.
Do not stop or change any inhaler before the test on your own. Ask the team whether to take it that morning.Before the test
How should you prepare for a lung function test?
- Wear loose clothes that do not squeeze your chest or waist
- Eat a light meal only, as a full stomach makes deep breaths hard
- Do not smoke on the day of the test
- Avoid heavy exercise just before the appointment
- Bring your inhalers and a list of your medicines
- Ask whether to take your inhaler that morning
Commonly believed
What do people often get wrong about breathing tests?
"A normal chest X-ray means my lungs are fine."
An X-ray shows the shape of the lungs. It does not measure how well they work. A person can have a clear X-ray and still have narrowed airways that show up only on spirometry.
"If I blow gently, the test is safer."
A gentle blow gives a falsely poor result, which may delay or change your surgery. Give your full effort, unless you have been told not to. Say if you feel dizzy.
"He smoked for years, so stopping now is pointless."
Stopping before surgery still helps. The airways clear mucus better and the blood carries more oxygen. The team can help with support to quit.
"Poor results mean I cannot have any operation."
Results are weighed against the operation planned. Many people with COPD have cancer surgery after their breathing is improved. When a large lung operation is unsafe, other options may still be discussed.
Questions we are asked
Common questions about lung function tests before surgery
Is the lung function test uncomfortable?
It is not painful, but it is tiring. Blowing hard several times can make you feel light-headed, cough or a little short of breath for a moment. You rest between each attempt. Tell the technician if you feel unwell, and they will wait before trying again.
How long does the test take?
Spirometry on its own is usually quick. If gas transfer, an inhaler test or a walking test is added, the visit takes longer. Arrive early, bring someone with you if you tire easily, and plan for some waiting time at a busy lab.
Why is a lung test needed for stomach or food pipe surgery?
These operations are close to the diaphragm, the main breathing muscle. After them, deep breathing and coughing are painful, so the lungs are at more risk of infection. The test helps the team prepare your breathing in advance.
My father cannot blow properly. What then?
Some people cannot manage the test because of weakness, missing teeth, confusion or a tracheostomy. Tell the team. Walking tests, oxygen readings, a careful history or other tests can still help judge how well his lungs will cope.
Do I stop my inhaler before the test?
Ask the team or the lab when you book. Some labs want certain inhalers paused so they can see your true airway function, and others want you on your usual treatment. Never stop an inhaler on your own, especially if you use it for asthma attacks.
Can breathing exercises improve my result?
They can improve how well you breathe and cough after surgery, even when the test numbers change only a little. Walking, stopping smoking and using inhalers as prescribed all help. Ask for a physiotherapist to show you the right exercises.
I had radiotherapy to the chest. Does that matter?
Yes, mention it. Radiotherapy and some chemotherapy drugs can stiffen lung tissue over time. A gas transfer test is often added to check how well oxygen moves into the blood. Bring your treatment summary to the appointment.
Is the test covered by Aarogyasri or insurance?
It is often covered when it is part of an approved cancer surgery plan. Aarogyasri, CGHS, ECHS, EHS and cashless insurance each have their own rules. Call the helpline with your card or policy details and the team can check your cover.
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Sources
- NHS — Spirometry
- NICE — Routine preoperative tests for elective surgery (NG45)
- Cancer Research UK — Surgery for cancer
- Royal College of Anaesthetists — Patient information
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
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Breathing Exercises Before Chest and Abdominal SurgeryThe exercises that protect your lungs after an operationSurgery With COPD or AsthmaHow surgery is planned around a known lung conditionStopping Smoking Before Cancer SurgeryWhy quitting still helps, even close to the dateFitness, Tests and PrehabilitationEvery guide on getting ready for an operation
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