Many respiratory conditions can look alike from the outside — a cough, some wheezing, breathlessness on the stairs — but they behave very differently inside the lungs and need very different treatment. A pulmonary function test is how doctors move from guessing to measuring. Alliance Hospital BD’s One Stop Respiratory Center in Shyamoli offers pulmonary function testing, including spirometry, for patients across Shyamoli and nearby Mohammadpur.
This guide explains what a pulmonary function test measures, who needs one, how to prepare, and what the results can tell you.
A pulmonary function test (PFT) is a group of non-invasive breathing tests that measure how well the lungs are working — how much air they can hold, how quickly air moves in and out, and how efficiently oxygen passes into the blood. The most common and widely used of these is spirometry, where the patient breathes into a mouthpiece connected to a device that records airflow and volume. It’s quick, painless, and gives objective numbers rather than relying on how someone feels.
Pulmonary function testing serves several purposes: confirming or ruling out a suspected lung condition, measuring how severe an existing one is, tracking whether it’s changing over time, and checking whether treatment is actually working. It’s also commonly used to assess lung function before certain surgeries, and to monitor people with long-term exposure to dust, fumes, or smoking.
A few key measurements form the core of most results. FVC (forced vital capacity) is the total amount of air a person can forcefully exhale after taking a deep breath. FEV1 (forced expiratory volume in one second) is how much of that air comes out in the first second. The ratio between the two helps distinguish obstructive patterns, where airways are narrowed and air is hard to push out, as in asthma or COPD, from restrictive patterns, where the lungs can’t fully expand, as in interstitial lung disease. More comprehensive testing can also measure total lung volumes and how well oxygen crosses from the lungs into the blood.
Results are interpreted against your own profile. Normal values depend on age, height, sex, and ethnicity, so a number only means something when compared to what’s expected for that individual. This is why the test is best interpreted by a specialist rather than read against a generic chart.
Preparation is simple but does affect accuracy. Patients are generally advised to avoid smoking for several hours beforehand, avoid heavy meals and strenuous exercise right before the test, and wear comfortable, non-restrictive clothing. Some inhalers or breathing medications may need to be held back temporarily before testing, but this should only be done on a doctor’s instruction — never stopped on one’s own. Mentioning all current medications at the time of booking helps the team advise correctly.
The patient sits comfortably, a soft clip is placed on the nose, and they breathe through a mouthpiece following instructions from the technician — typically taking a deep breath and then blowing out as hard and fast as possible, repeated a few times to ensure consistent readings. The whole test usually takes under 30 minutes. Some people feel briefly lightheaded or tired after the forceful breathing, which passes quickly. According to the NHS’s overview of spirometry, it’s considered a safe test for most people, though it’s not suitable in certain situations, such as shortly after a heart attack or recent eye or chest surgery — another reason a doctor’s review beforehand matters.
Without testing, respiratory conditions are often treated based on symptoms alone, which can lead to the wrong medication or delayed diagnosis. Pulmonary function results give the treating doctor a baseline to work from, confirm whether a suspected diagnosis is actually correct, and make it possible to see — in numbers — whether treatment is improving lung function over time. For long-term conditions like asthma and COPD, repeat testing at intervals is a standard way of tracking progress.
Alliance Hospital’s Chest Medicine department is led by Prof. Dr. Md. Rashidul Hasan, holding an MD in Chest Diseases, who interprets results in the context of each patient’s symptoms and history rather than in isolation. For a broader look at the respiratory care available, see our related article: Best Pulmonologist in Shyamoli.
Patients from Mohammadpur, Adabor, and Kallyanpur can reach the One Stop Respiratory Center within a short drive given its location just off Ring Road in Shyamoli, with spirometry and consultation available in the same visit near Mohammadpur.
Living with a persistent cough, wheezing, or breathlessness that hasn’t been properly assessed? Alliance Hospital’s Chest Medicine team in Shyamoli can arrange a pulmonary function test and consultation.
No. It involves breathing into a mouthpiece and is non-invasive. The forceful breathing can leave some people briefly tired or lightheaded, but this passes quickly.
Typically around 15 to 30 minutes, including instructions and repeated attempts to make sure the readings are consistent.
Sometimes, depending on the type of inhaler and what’s being assessed. Never stop on your own — ask the clinic or your doctor at the time of booking so you get specific instructions.
It’s the key objective test for both, but a diagnosis also takes into account symptoms, history, examination, and sometimes other tests. The specialist interprets the result alongside the full picture.
It depends on the condition. For ongoing conditions like asthma or COPD, repeat testing every few months to once a year is common, to track whether lung function is stable or changing.
