Pulmonary Function Tests at IRC Islamabad
By Dr Jehangir Khan, Consultant Pulmonologist · Reviewed by Dr Muhammad Israr · Updated 4 Oct 2026
In the video: Dr Jehangir Khan walks through the five devices we use at IRC: the spirometer, the lung age monitor, the NObreath FeNO analyser, the exhaled CO monitor and the peak flow meter. This page explains what each one tells your doctor and how to get ready.
Pulmonary function tests (PFTs) are painless breathing tests. No needles, no radiation. Different tests answer different questions, so you rarely need all of them. At Islamabad Respiratory Clinic, G-11 Markaz (inside Saeed International Hospital), your doctor chooses the tests after hearing your symptoms.
Which test answers which question?
| Test | Question it answers | Takes |
|---|---|---|
| Spirometry | Are my airways narrowed? How severe? | 10–15 min |
| FeNO | Is there allergic (Type 2) inflammation in my airways? | About 5 min |
| Lung age | How do my lungs compare with someone my age who has healthy lungs? | Same blow as spirometry |
| Exhaled CO | Have I really cut down or stopped smoking? | Under 2 min |
| Peak flow diary | Does my breathing change from day to day, as in asthma? | 1–2 weeks at home |
The tests, one by one
FeNO (exhaled nitric oxide)
You breathe in fully, then blow out slowly and steadily into the NObreath device for about 10 seconds while watching an on-screen guide. The device measures nitric oxide in your breath, a marker of allergic airway inflammation. A high reading supports asthma that responds to inhaled steroids. A low reading makes that type of asthma less likely, but does not rule out other kinds. It is always read alongside your symptoms and spirometry.
Lung age
Lung age is calculated from your spirometry result. If you are 35 but your lungs perform like an average 55-year-old's, that gap is your lung age. Smokers often find it more motivating than a raw percentage. It is a counselling tool, not a diagnosis.
Exhaled carbon monoxide (CO)
You hold your breath for a few seconds, then blow gently into a small monitor. Smoking raises CO in your breath within hours, so the number gives you honest, same-day feedback during a quit attempt. Non-smokers are typically in the single digits (ppm). Regular smokers are usually well above that.
Peak flow
A peak flow meter is a small handheld tube. You blow hard once, morning and evening, and write the best of three blows in a diary. Asthma is variable, so spirometry can be normal on the day you visit. Large swings in your diary over one to two weeks, often 20% or more, point towards asthma even then.
Spirometry
This is the main airflow test (FEV1, FVC and their ratio). It has its own page with procedure, normal values and cost: Spirometry test in Islamabad.
Which tests might I need?
- Cough that lingers for weeks, or night-time wheeze: spirometry, FeNO and possibly a peak flow diary. See asthma in Islamabad.
- Smoker with breathlessness: spirometry with bronchodilator, plus lung age and CO. See COPD treatment.
- Known asthma, checking control: FeNO and spirometry, plus an inhaler technique review.
- Trying to quit smoking: CO and lung age at each visit to track progress.
- Allergic symptoms with chest tightness: FeNO, then consider allergy testing.
Test-day order and preparation
If several tests are done in one visit, FeNO is done first, because forceful blowing in spirometry can lower the FeNO reading. For general spirometry preparation (smoking, exercise, meals, inhalers), see the spirometry preparation list. Extra points for this visit:
- Do not eat or drink anything except water for about an hour before FeNO. Skip coffee and tea in that hour.
- Tell the technician if you have a cold or chest infection. It can change results.
- Bring your inhalers, any past reports and your peak flow diary if you already keep one.
- Do not stop prescribed medicines unless your doctor tells you to.
What do the numbers mean?
FeNO (adults): below about 25 ppb is low, 25–50 ppb is intermediate, above 50 ppb is high.
Exhaled CO: the lower the better. A falling number across visits shows you are cutting down.
Peak flow: your own best value matters more than a chart. Your doctor looks at the gap between morning and evening and the dips below your best.
These ranges are general guides. Your doctor interprets them with your symptoms, age, height and medical history. Never self-adjust treatment from a single number.
Cost, timing and booking
Cost: depends on which tests are needed. Call for current single-test and package pricing.
Time: a basic assessment is roughly 20–40 minutes. More tests take longer.
Reports: same-day reporting may be available.
Where: IRC Clinic, Saeed International Hospital, 1 Hospital Road, G-11 Markaz, Islamabad. Get directions
Questions patients ask
Do I need all five tests?
No. Most people need two or three. Your doctor picks them from your symptoms.
Does a normal spirometry rule out asthma?
No. Asthma comes and goes. FeNO or a peak flow diary can pick up what a single normal spirometry misses.
Is FeNO painful or risky?
No. It is a slow, steady breath into a mouthpiece, with no side effects. Children from about 7 years can usually do it.
Can I do the CO test if I have already quit?
Yes. A low reading confirms that you are smoke-free, and it is a good milestone to see.
Should I stop my inhaler before the tests?
Only if the clinic or your doctor tells you to. Never stop a prescribed inhaler on your own.
Related guides
- Spirometry test: cost, procedure and normal values
- Asthma in Islamabad · Inhalers for asthma
- COPD treatment · Allergy testing
- یہ صفحہ اردو میں پڑھیں
Medical information: This page is for general education and does not replace a consultation. Test choice and interpretation should be individualised by a qualified doctor. Islamabad Respiratory Clinic (IRC) · 1 Hospital Road, G-11 Markaz, Islamabad · 0343 1510025 · ircchest@gmail.com