Lung Function Test in Sharjah
Medically reviewed by Dar Al Kamal Team
What is pulmonary function testing?
Pulmonary function testing is a group of breathing tests that together build a detailed picture of how the lungs work. Spirometry, the single core test, measures how much air you can blow out and how fast. A full set of tests adds two further measurements, each answering a different question:
- Lung volumes show the total amount of air your lungs hold, including the air that stays in the chest after you breathe out as far as you can. This separates lungs that are narrowed, as in asthma and COPD, from lungs that are small or stiff, as in scarring of the lung tissue or weakness of the breathing muscles.
- Gas transfer, sometimes written as DLCO or TLCO, measures how easily gas crosses from the air sacs into the bloodstream. It reflects the thin membrane where oxygen enters the blood, and it can be reduced even when spirometry looks normal.
At Dar Al Kamal Hospital, Sharjah, the pulmonologist reads all three results together, because the pattern across the tests is often more informative than any one number.
Who needs it
Your doctor may recommend full lung function testing when spirometry alone leaves a question open. Common reasons include:
- Suspected or known interstitial lung disease, where gas transfer and lung volumes help confirm the diagnosis and track change over time; see interstitial lung disease care
- Unexplained breathlessness, particularly when a chest X-ray, heart tests and blood count have come back normal
- Before major surgery, especially operations on the chest or upper abdomen, to judge how well the lungs will cope; see pre-operative respiratory assessment
- Work exposure to dust, fumes or chemicals in construction, quarrying, metalwork or industrial settings
- Treatments that can affect the lungs, where a baseline and repeat tests help the team act early
- Known COPD or asthma that behaves differently from what the diagnosis would predict
For many patients, spirometry is the right first step, and the fuller tests are added when the result or the symptoms call for more detail.
What happens
The tests take place in a lung function room with a technician guiding each breath. You sit upright with a soft clip on your nose so that all your breathing goes through a mouthpiece. Height and weight are measured first, because expected values are calculated from your age, height and sex.
Spirometry usually comes first: a full breath in, then a hard, fast blow out, repeated a few times so the best efforts can be compared.
Lung volumes are often measured while you sit inside a clear, sealed booth, similar in size to a telephone box. You can see out and talk to the technician throughout, and the door can be opened at any moment. You breathe quietly through the mouthpiece and then pant gently against a brief closed valve; the booth measures tiny pressure changes to calculate the air in your chest. Some centres use a gas-breathing method instead, and either way the technician explains each step.
Gas transfer is a single breath-hold test. You breathe out fully, take a deep breath of a test gas containing a very small, safe amount of carbon monoxide and a harmless tracer gas, hold your breath briefly, then breathe out. The machine compares what went in with what came out to see how much crossed into the blood. Because haemoglobin carries the gas, a recent blood count helps the pulmonologist interpret this result accurately.
Preparing for it
Good preparation makes the results reliable:
- Inhalers: you may be asked to pause some inhalers for a set time before the test. Follow the instructions given when you book, and bring every inhaler with you.
- Smoking: avoid smoking on the day of the test. This includes cigarettes, shisha, dokha and midwakh, and vaping. Recent smoke raises carbon monoxide in the blood and lowers the gas transfer reading.
- Meals: eat lightly beforehand, since a full stomach limits how deeply you can breathe in.
- Clothing: wear loose clothes that allow a full breath.
- Exercise: keep to gentle activity beforehand and arrive with time to settle.
Tell the team when you book if you have had recent chest, eye or abdominal surgery, a recent heart problem, or a chest infection in the past few weeks, as the test date may be adjusted. During Ramadan, discuss timing with the team, as an appointment can be arranged around your fast and your inhaler plan.
Afterwards
Most people feel a little tired or light-headed from the repeated deep breaths, and this settles quickly. You can resume usual inhalers, food and activity straight away, and drive home.
The pulmonologist reviews the full set of results with your history, examination and any imaging, such as a chest X-ray or CT scan arranged through chest imaging. Repeat testing is useful for tracking a condition, so keep a copy of your report and bring earlier reports from other hospitals.
Contact the hospital if you have questions about your results or your symptoms change while you wait for follow-up. If you develop severe breathlessness, chest pain or wheeze that persists despite your reliever inhaler, call emergency services or go to the nearest emergency department.
Cost and insurance
Most UAE health insurance plans cover lung function testing requested by a doctor for symptoms or a known lung condition. The fuller tests, lung volumes and gas transfer, sometimes need insurance pre-approval, and pre-operative testing may be billed under the surgical episode. Dar Al Kamal Hospital, Sharjah can help you check your cover before the test on 06 599 7777.
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Frequently asked questions
What is the difference between spirometry and a full lung function test?
Spirometry measures how much air you can blow out and how fast, while a full lung function test adds lung volumes and gas transfer to show how much air the lungs hold and how well oxygen crosses into the blood. Spirometry is often enough for asthma and COPD, and the fuller tests are added when the question is about stiff lungs, unexplained breathlessness or fitness for surgery.
Is the lung volume booth claustrophobic?
The lung volume booth is made of clear panels, so you can see out and talk to the technician throughout, and the door can be opened whenever you need. If enclosed spaces worry you, tell the team beforehand, as there is often an alternative way to measure lung volumes.
Why was I told not to smoke before the gas transfer test?
Smoking before a gas transfer test raises the carbon monoxide level in your blood, which makes the result look worse than your lungs really are. This applies to cigarettes, shisha, dokha, midwakh and vaping on the day of the test.
Should I stop my inhalers before a lung function test?
Some inhalers are paused for a set time before a lung function test so the baseline is accurate, but you should only do this as instructed by the team when you book. If you need your reliever for symptoms, take it and tell the technician on arrival.
What are the risks of a lung function test?
Lung function tests are very low risk; the main effects are brief light-headedness, tiredness, coughing or chest tightness from repeated hard breathing, which settle quickly. The tests depend on your effort and technique, so results can be limited if you are unwell or unable to breathe out fully, and a normal result does not rule out every lung or heart cause of breathlessness. The small amount of carbon monoxide in the gas transfer test is safe and leaves the body quickly.
Can a lung function test diagnose interstitial lung disease on its own?
A lung function test cannot diagnose interstitial lung disease on its own, but a reduced gas transfer and small lung volumes are important clues. The diagnosis is made by combining these results with a CT scan of the chest, your history and blood tests.
Why do I need a lung function test before surgery?
A lung function test before surgery helps the surgical and anaesthetic team judge how well your lungs will cope with the operation and recovery. It is most often requested before chest or upper abdominal operations, or when you have known lung disease or unexplained breathlessness.
Is a lung function test covered by insurance in the UAE?
Most UAE insurance plans cover a lung function test requested by a doctor for symptoms or a known lung condition, although lung volumes and gas transfer sometimes need pre-approval. Confirm your cover with Dar Al Kamal Hospital, Sharjah on 06 599 7777.
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