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. It can help diagnose the flu, COVID-19, RSV, whooping cough, meningitis, and MRSA. There are three common collection methods: anterior nares (front of nostrils), nasal mid-turbinate (back of nostrils), and nasopharyngeal (upper throat). The test may cause temporary tickling, coughing, or gagging. A negative result means no harmful germs were found; a positive result means a specific germ was found. Your provider will consider your symptoms and other factors to guide treatment.
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.
Sample may be collected from the front part of your nostrils (anterior nares), the back of your nostrils (nasal mid-turbinate), or the nasopharynx (uppermost part of nose and throat). For anterior nares: tilt head back, gently insert swab, rotate in 4-5 sweeping circles for 10-15 seconds, then repeat in the other nostril. For NMT swab: tilt head back, insert swab until it stops, rotate for 10-15 seconds, then repeat in the other nostril. For nasopharyngeal swab: tilt head back, provider inserts long swab into nostril until it reaches nasopharynx, rotates for 10-15 seconds; may only need one nostril. You or your provider may collect the sample; follow provider instructions for packaging and returning the 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
The test looks for viruses and bacteria that cause respiratory infections. Your provider will interpret the results along with your symptoms and medical history.
- Negative: No harmful viruses or bacteria were found in your sample. Limitation: The test may not detect all types of respiratory infections. Next step: Your provider may recommend other tests or treatments based on your symptoms.
- Positive: A specific type of harmful virus or bacteria was found in your sample. Limitation: A positive result does not always mean you have a severe infection. Your provider will assess the specific pathogen found. Next step: Follow your provider's recommendations for treatment and preventing spread of the infection.
- 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?