You are climbing a flight of stairs, and halfway through, you start to feel shortness of breath and an unsettling wheeze. Not only that, you are sleeping at night and start to cough vigorously and persistently for days. Nine out of ten times, we shrug off these symptoms as a lingering cold, poor fitness or allergies.

However, a lot of the times, it happens due to a chronic inflammatory condition,asthma. The primary clinical barrier to managing asthma is not the absence of medication but the delay or inaccuracy of initial diagnoses. This explains why the PFT or pulmonary function test is so pivotal to the diagnosis of asthma.

Our pulmonologists at Jindal Chest Clinic rely on objective, numbers-driven medical testing, and PFT is the most important one for asthma diagnosis. More on that will be highlighted in this guide.

What is Asthma and How Does it Manifest Clinically?

Asthma occurs when there is a chronic inflammation of the airways. For such patients, the airways become narrower due to inflammation and also overly sensitive to a lot of triggers that produce excess mucus. The narrowing, in turn, causes airflow obstruction and thereby leads to breathing difficulties.

Hence, the most common asthma symptoms involve breathing issues, including:

• Wheezing
• Persistent coughing
• Shortness of breath
• Chest tightness
• Difficulty breathing during exercise
• Night-time or early morning respiratory symptoms

All that said, the severity and frequency of the symptoms can vary a lot among patients. While some patients experience occasional episodes, others have to deal with persistent symptoms daily.

Also, a lot of the symptoms of asthma can overlap with other chronic respiratory symptoms like chronic obstructive pulmonary disease (COPD), bronchitis, allergies, respiratory infections, and even heart-related issues, which explains the need for accurate diagnosis.

What is a Pulmonary Function Test or PFT?

Now that you have a better understanding of what asthma is, it is also vital that you are aware of what PFT is and what it comprises.

A pulmonary function test or PFT is a non-invasive and comprehensive set of diagnostic tests that measure how well the lungs expand, how much air they can hold, and how efficiently they exchange oxygen and carbon dioxide across the respiratory membrane. It provides pulmonologists with precise quantitative data they need to further personalise an asthma patient’s treatment plan.

There are many advanced components to PFT, including body plethysmography,gas diffusion studies (DLCO), etc. However, the most important part of the test is spirometry.

So, what happens during a spirometry session? A patient takes a maximal deep breath and then forcefully exhales all the air from their lungs as hard and fast as possible into a specialized mouthpiece connected to a computer. It calculates forced vital capacity and forced expiratory volume in 1 second.

The ratio between these two components (FEV1/FVC) helps the doctors determine whether an obstructive lung pattern is present, establishing a clear baseline for your respiratory health.

Are Symptoms Enough for Asthma Diagnosis?

Well, no.

But why?

Relying purely on classic clinical indicators like wheezing or coughing to diagnose asthma introduces significant room for error. There are several distinct medical conditions that mirror the exact clinical presentation of asthma, which can lead to a misdiagnosis.

This is one of the reasons why clinical diagnostic tools, including pulmonary function tests, are used to diagnose whether or not the patient actually has asthma or other chronic illnesses.

What is the Bronchodilator Reversibility Test?

One of the primary factors that differentiates asthma from a lot of the other chronic respiratory conditions is reversibility. For example, severe lung diseases like COPD involve permanent, structural damage to the lung tissues that limits airflow.

Asthma, on the other hand, is dynamic. This means that the airway narrowing in an asthmatic patient can change, either spontaneously or under the influence of targeted medical therapy.

To prove this diagnostic trait, our specialists at Jindal Chest Clinic often perform a Bronchodilator Reversibility Test during the PFT session. It involves the following steps:

1. Baseline spirometry

The first step in the process is a baseline spirometry. Here, the patient performs an initial round of forceful exhalations to establish their current, unaltered lung function metrics.

2. Medication administration

Once the initial spirometry is done, the patient inhales a standardised dose of a fast-acting rescue bronchodilator medication via a spacer device. The role of this medicine is to quickly relax the smooth muscles surrounding the bronchioles.

3. Rest period

Then, the patient rests comfortably for 15–30 minutes, allowing the bronchodilator to reach peak therapeutic effect within the lung tissues.

4. Post-bronchodilator spirometry

Following the rest period, the patient again repeats the spirometry test and the software then recalculates the lung volumes.

Now, coming to the asthma diagnosis. To confirm a formal diagnosis of asthma, international guidelines require a positive reversibility threshold: an increase in FEV1 of greater than or equal to 12% AND an absolute volume increase of at least 200 mL compared to the baseline measurement.

What Happens After Asthma Diagnosis?

Now, coming to the main point of discussion, “What next?” Once the patient receives a formal diagnosis of asthma after the pulmonary function test, the next step is personalised management of the disease.

It involves one of the following, depending on the severity of the condition:

Asthma Severity Class	Daytime Symptom Frequency	Nighttime Awakenings	Predicted FEV1 Value
Intermittent	≤ 2 days per week	≤ 2 times per month	> 80%
Mild Persistent	> 2 days per week, but not daily	3 to 4 times per month	> 80%
Moderate Persistent	Daily symptoms	> 1 time per week, but not nightly	60% to 80%
Severe Persistent	Throughout the day, every day	Often 7 times per week	< 60%

Determining the exact severity of the airway obstruction is paramount, primarily because it prevents both undertreatment and overtreatment. For example, a patient presenting with an FEV1 below 60% requires immediate, aggressive anti-inflammatory therapy to avoid life-threatening flare-ups. On the flip side, someone with intermittent asthma may only need a rescue inhaler for occasional symptoms. The PFT data provides our pulmonologists the required data to then personalise the patient’s treatment plans accordingly.

How to Prepare for Your PFT Appointment at Jindal Chest Clinic?

If you are scheduled for a pulmonary function test at Jindal Chest Clinic, there are certain pre-test guidelines you need to follow.

These include:

• Do not use quick-relief rescue inhalers for at least 4 to 6 hours before the test.
• Hold long-acting maintenance inhalers for 12 to 24 hours prior to testing, based on specific instructions from your care team.
• Avoid smoking or vaping for at least 1 hour before the test, as nicotine directly triggers acute airway irritation.
• Refrain from eating a heavy, dense meal right before your appointment. A full stomach can physically restrict your diaphragm from expanding fully, artificially lowering your test results.
• Wear loose-fitting, comfortable clothing around your chest and abdomen so your breathing isn't restricted.

All of the dos and don’ts prior to the PFT will be discussed with you in detail by our pulmonologists before the procedure so you aren’t blindsided.

Who and When Should You Consider a PFT for Potential Asthma Diagnosis?

With all that discussed, you must be wondering, “When should I even consider undergoing PFT for asthma diagnosis? Is it even necessary?”

Well, yes, it is. You need to undergo PFT for asthma evaluation, especially when you are experiencing:

• Recurrent wheezing
• Persistent cough
• Unexplained breathlessness
• Chest tightness
• Frequent respiratory infections
• Exercise-related breathing problems
• Family history of asthma
• Allergic conditions with respiratory symptoms

Not just for the initial diagnosis, a lot of asthma patients also require periodic PFTs to monitor their disease and how well the treatment is working for them.

What are the Benefits of Early Asthma Diagnosis Through PFT?

Every medical condition benefits from an early diagnosis; so does asthma. If you have been experiencing the typical asthma symptoms and brushing them aside as “normal” or “regular”, well, it is time to change that mindset.

In fact, early asthma diagnosis through PFT presents a lot of benefits, including:

• Better symptom control
• Reduced risks of severe attacks or flare-ups
• Improved quality of life
• Prevention of long-term lung damage
• More personalised treatment

Asthma diagnosis requires expertise and precision, which is why consulting experienced pulmonologists like ours at Jindal Chest Clinic will not only help you receive a diagnosis but also a customised treatment plan that helps you breathe more freely.

Get Precise Asthma Diagnosis at Jindal Chest Clinic!

Asthma does not have to limit your quality of life. With an accurate diagnosis and an expert management plan, you can live free from constant coughing, wheezing, and the sudden fear of breathlessness.

You do not have to guess about your respiratory health. A Pulmonary Function Test provides the clear, actionable numbers needed to understand your lungs, confirm an accurate diagnosis, and tailor a treatment strategy specifically for you.

Schedule a comprehensive consultation at Jindal Chest Clinic to meet with experienced respiratory specialists and book your Pulmonary Function Test today.