Getting your lungs checked typically starts with a visit to your primary care doctor, who can perform basic breathing tests in the office and order imaging or refer you to a lung specialist if needed. The specific tests you’ll get depend on your symptoms, age, and risk factors, but most people can have their lung function measured in a single appointment.
Start With Your Primary Care Doctor
Your primary care provider is the gateway to lung testing. They can order chest X-rays, run a basic breathing test called spirometry, and decide whether you need more advanced evaluation. For many concerns, like a lingering cough, mild shortness of breath, or a general wellness check, this is the only appointment you’ll need.
If your results suggest something more complex, your doctor will refer you to a pulmonologist. Referrals are typically made when asthma or COPD isn’t responding to standard treatment, when imaging reveals a lung nodule larger than 8 millimeters, when you’re coughing up blood without a clear cause, or when shortness of breath remains unexplained after initial testing. Most insurance plans require this referral before covering a specialist visit.
Spirometry: The Core Breathing Test
Spirometry is the most common lung function test and the one your doctor is most likely to order first. You breathe in deeply, then blow as hard and fast as you can into a tube connected to a small machine called a spirometer. It measures two things: the total amount of air you can push out of your lungs and how much of that air comes out in the first second.
In healthy lungs, about 75% to 85% of your total air comes out in that first second. When that ratio drops below 70%, it suggests an obstructive condition like asthma or COPD, where your airways are narrowed. If both the total volume and the first-second volume are low but the ratio between them is normal, that points toward a restrictive problem, where the lungs themselves can’t fully expand.
Your doctor may ask you to inhale a medication that opens your airways, then repeat the test. Comparing the two sets of results helps distinguish between conditions. You might feel dizzy, lightheaded, or tired from the deep breathing, and the forceful exhale can trigger coughing. The whole test takes about 15 to 30 minutes.
How to Prepare for Lung Function Tests
Preparation matters for accurate results. The National Heart, Lung, and Blood Institute recommends these steps before spirometry and other pulmonary function tests:
- Don’t eat a large meal within two hours of the test.
- Skip heavy exercise for at least 30 minutes beforehand.
- Avoid alcohol for at least four hours before testing.
- Don’t smoke on the day of your test.
- Wear loose clothing so you can take a full, deep breath without restriction.
- Bring your medication list with doses and frequency.
If you use inhalers, your doctor will likely ask you to pause them before the test. Short-acting rescue inhalers like albuterol need to be stopped six hours before. Long-acting inhalers require 24 to 36 hours. Your provider will give you specific instructions based on what you take.
Chest X-Rays and CT Scans
Imaging tests let your doctor see the physical structure of your lungs rather than just measuring airflow. A chest X-ray is fast, painless, and usually the first imaging test ordered. It can reveal pneumonia, fluid around the lungs, signs of emphysema, scarring, and some tumors. But it has limits: its sensitivity for detecting lung problems runs around 70% to 85%, and it can miss small lesions entirely.
CT scans are significantly more detailed. They take many cross-sectional images of your chest and combine them into a three-dimensional picture. Diagnostic accuracy for CT scans exceeds 95% for conditions like pneumonia, and specificity (the ability to correctly rule out disease) is above 90%. CT scans are better at distinguishing pneumonia from other conditions like blood clots in the lungs or cancer. Your doctor will typically order a CT scan when an X-ray is inconclusive, when symptoms don’t match a normal X-ray, or when they need to investigate a suspicious finding more closely.
Lung Cancer Screening
If you have a significant smoking history, you may qualify for annual lung cancer screening even without symptoms. The U.S. Preventive Services Task Force recommends yearly low-dose CT scans for people who meet all three criteria: a smoking history of at least 20 pack-years, currently smoking or having quit within the past 15 years, and being between 50 and 80 years old. A pack-year means averaging one pack per day for one year, so someone who smoked two packs daily for 10 years would qualify.
Medicare Part B covers this screening at no cost to you if your provider accepts assignment. You’ll need an order from your doctor, and before your first screening, you’ll have a shared decision-making visit to discuss the benefits and risks. Private insurance plans covered under the Affordable Care Act also generally cover this screening without a copay for eligible patients.
Monitoring Lung Health at Home
If you have asthma or another chronic lung condition, a peak flow meter lets you track your lung function between doctor visits. It’s a small handheld device you blow into as hard and fast as possible. The reading tells you how quickly you can move air out of your lungs.
To establish your baseline, use the meter twice a day for two weeks while your condition is well controlled, testing at the same times each morning and evening. The highest number you hit during that period becomes your personal best. From there, you compare daily readings against that number. A dropping peak flow can signal a flare-up before you even feel symptoms, giving you time to use a rescue inhaler or adjust your treatment plan. Keep a log of your readings so your doctor can spot trends over time.
Symptoms That Call for Lung Testing
Some symptoms clearly warrant getting your lungs evaluated: a cough lasting more than three weeks, shortness of breath during activities that didn’t used to wind you, wheezing, chest tightness, or coughing up blood. These are the situations where your doctor will likely start with spirometry and a chest X-ray together.
Certain signs point to more urgent breathing trouble. A bluish tint around the mouth, inside the lips, or on the fingernails means your body isn’t getting enough oxygen. Visible pulling of the skin below the neck or under the breastbone with each breath, known as retractions, indicates your body is working hard to draw air in. Pale or gray skin, unexplained sweating that feels cool or clammy, and needing to lean forward while sitting just to breathe are all signals to seek care quickly rather than scheduling a routine appointment.