Nasal Nitric Oxide Testing

This information was reviewed and approved by Val Keever (5/30/2026).

What Is Nasal Nitric Oxide Testing?

Nasal Nitric Oxide testing is used to diagnose Primary Ciliary Dyskinesia (PCD). Primary ciliary dyskinesia (PCD) is an inherited disease that affects tiny hair-like structures in the body called cilia. These cilia normally help move mucus, dust and bacteria out of the lungs and other parts of the body. In people with PCD, the cilia don’t work properly. They may not move at all, move in the wrong way or be missing entirely. This can lead to breathing problems, frequent lung infections and other health issues. PCD is a rare disease, affecting 1 in 7,600 people, according to the PCD Foundation.

Nasal nitric oxide (nNO) measurement: This noninvasive test measures nitric oxide (a gas) levels when you exhale. In people with PCD, nasal nitric oxide levels are much lower than normal and are often used as a first-line screening tool for diagnosis.

How do you get ready for the test?

Do not use any nasal sprays or tobacco within 4 hours prior to testing.

Do not eat any beets prior to testing.

Inform the technician if you have had any recent sinus infections, nasal surgeries or a bloody nose.

What is done during the test?

You will sit comfortably in a chair. You will be asked to place a soft pillow attached to a sample line into one side of your nose. You will be instructed to take a deep breath in through your mouth, then place a cardboard tube with a pinhole on the end in your mouth. This has a tight seal. You will gently blow steadily for about 20 seconds. This will be repeated 3 times on the right nostril, then 3 times on the left nostril. You will have a small rest time between each effort.

How long does the test take?

Testing takes about 10-15 minutes to complete.

Test results

The test results will be completed and entered into your medical record, often within 30 minutes of testing.