Nasal Swab
Reviewed
Also called: anterior nares test, nasal mid-turbinate swab, NMT swab, nasopharyngeal culture, nasopharyngeal (NP) swab
A nasal swab is a test that checks for viruses and bacteria that cause respiratory infections.
Specimen: Nasal swab sample from anterior nares, nasal mid-turbinate, or nasopharynx.
Why this test may be ordered
- You have symptoms of a respiratory infection, such as cough, fever, stuffy or runny nose, sore throat, headache, fatigue, or muscle aches.
- Your provider needs to identify the specific cause of a respiratory infection to guide treatment.
- You may have been exposed to a contagious respiratory illness and need testing for diagnosis or public health reasons.
Preparation and collection
You don't need any special preparations for a nasal swab.
The test may be done by taking a sample of cells from inside your nostrils or from the nasopharynx, the uppermost part of your nose and throat. If you only swab one nostril, don't rotate the swab in your nostril, or only keep the swab in one area, you may not get a good sample.
The test may tickle your throat or cause you to cough. A nasopharyngeal swab may be uncomfortable and cause coughing or gagging. All these effects are temporary.
Understanding results
To understand the results of a nasal swab test, your provider may consider your symptoms, medical history, and the results of other tests.
- Negative: A negative result means no harmful viruses or bacteria were found in your sample. Limitation: If you only swab one nostril, don't rotate the swab in your nostril, or only keep the swab in one area, you may not get a good sample. Next step: To understand the results of a nasal swab test, your provider may consider your symptoms, medical history, and the results of other tests.
- Positive: A positive result means a specific type of harmful virus or bacteria was found in your sample. Limitation: To understand the results of a nasal swab test, your provider may consider your symptoms, medical history, and the results of other tests. Next step: If you are diagnosed with an infection, follow your provider's recommendations for treating your illness.
- A negative result means no harmful viruses or bacteria were found in the sample, but it does not rule out infection if the sample was not collected properly or if the pathogen is present in low numbers.
- A positive result means a specific type of harmful virus or bacteria was found, but your provider will consider your symptoms, medical history, and other test results to confirm the diagnosis.
- The test may not detect all possible causes of respiratory infection, and results should be interpreted by a healthcare professional.
What to do next
If you are diagnosed with an infection, follow your provider's recommendations for treating your illness. This may include medicines and steps to prevent spreading the infection.
- Do you have symptoms such as cough, fever, stuffy or runny nose, sore throat, headache, fatigue, or muscle aches?
- Have you been exposed to someone with a respiratory infection?
- Do you have a medical condition that increases your risk for severe respiratory illness?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.