A patient came in last month, a runner in her forties, frustrated that she kept stopping mid-jog to catch her breath. "I'm just out of shape," she told me. Maybe. But that kind of breathlessness deserves a real answer, not a shrug. One of the clearest ways to get that answer is a pulmonary function test referral, and in my Los Angeles practice it's one of the quieter tools I lean on when someone's breathing isn't behaving the way it should.
A pulmonary function test, or PFT, measures how well your lungs move air in and out and how efficiently they deliver oxygen to your blood. It turns a vague symptom into actual numbers. That matters, because "I get winded" can mean a dozen different things, and I'd rather know which one we're dealing with.
What is a pulmonary function test, and why might I need one?
A pulmonary function test is a painless breathing test that shows how much air your lungs can hold and how fast you can push it out. The most common version is spirometry, where you take a big breath and blow hard into a mouthpiece.
I usually refer patients for one when there's a pattern I want to understand better. Shortness of breath that doesn't add up. A chronic cough. Wheezing. A long history of smoking. Sometimes I order it to confirm a diagnosis I suspect, and sometimes to rule one out.
It also helps me track how someone is doing over time. If we've started a treatment, repeat testing tells me whether it's actually working or whether we need to change course.
How does a PFT help with asthma or COPD?
A pulmonary function test helps confirm whether you have asthma or COPD and shows how much your airways are narrowed. These two conditions can feel similar from the outside, but they behave differently, and they're managed differently.
With asthma, the airway narrowing often improves a lot after an inhaled medication. The test can capture that change. With COPD, the obstruction tends to be more fixed. Seeing which pattern your lungs follow helps me and any specialist we involve choose the right approach.
Here's what testing can help sort out:
- Whether your breathing trouble is coming from your airways at all
- How severe the narrowing is right now
- Whether your lungs respond to a bronchodilator
- How you're trending across follow-up visits
I often tell patients that the goal isn't just a label. It's a plan we can actually follow and measure.
What happens during the test, and does it hurt?
Nothing about a pulmonary function test hurts. You'll sit, wear a soft nose clip, and breathe into a tube following the technician's cues, usually a few deep breaths and a couple of hard, fast exhales.
You may be asked to repeat the breathing after an inhaled medication so the team can see if your numbers improve. The whole thing typically takes under an hour. Some people feel briefly lightheaded from the big breaths, which passes quickly.
A few simple things help the results come out clean. I'll usually ask patients to avoid heavy meals right before, skip smoking that day, and check with me about pausing certain inhalers ahead of time so we get an accurate read.
How do I prepare, and what comes next?
The best preparation is wearing comfortable clothing and bringing a current list of your inhalers and medications. I review every result personally, so we sit down together and talk through what the numbers mean for you.
If the test points toward asthma or COPD, we build a plan. That might include inhaled bronchodilator therapy, lifestyle changes, and clear instructions on what to do when symptoms flare. If your situation is more complex, I coordinate a specialist referral to a pulmonologist and stay involved so nothing slips through the cracks.
Because I run a small membership practice, I have time for this. I'm not rushing you out the door before you understand your own lungs.
One more thing I want patients to hear: breathing problems are common, and they're often very treatable once we know what we're working with. Getting tested isn't a sign something is terribly wrong. It's a smart, proactive step.
If you're in Los Angeles and your breathing has felt off lately, or you've been told you "might have" asthma or COPD and never gotten a clear answer, let's talk. I'd be glad to walk you through whether a pulmonary function test makes sense for you. Reach out anytime and we'll figure out the next step together.