Are you heading in for a flu or COVID-19 test? You may be wondering what the difference between a nasal swab test and a nasopharyngeal test is. In this article, we explain the core difference between these two tests, as well as the swabs used to collect them.
What is the nasal swab method?
The nasal swab method is done with a swab to collect a diagnostic sample from the nasal membrane. The nasal swab test (commonly referred to as an anterior nasal test), involves inserting a swab into the nostril about 0.5-.75 inches deep, and while touching the sides of the nasal wall is rotated for 10-15 seconds in one nostril, then with the same swab, collected the same way in the other nostril. Because this method is less invasive, it is usually more comfortable for the patient—and also the method used when self-testing.
Check out the CDC-recommended guidelines for COVID-19 nasal swab testing here.
Swabs used for the nasal method of collection are typically a medium-sized tip that is made from an absorbent material, usually flocked fibers, spun polyester, or medical-grade foam. The handle of a nasal swab used for this diagnostic testing is usually made of polystyrene.
What is the nasopharyngeal swabbing method?
The nasopharyngeal collection method collects a sample from the nasopharynx, which is the upper part of the throat behind the nose. For this test, a small, mini-tipped swab is inserted into the nostril parallel to the chin, until resistance is felt. The swab is inserted no deeper than half the distance between the nostrils and the ear. The swab will then be rotated a few times while holding in place, then, slowly removed while gently rotating. If the tip of the swab is fully saturated with specimen, it may not be necessary to collect a sample from both nostrils. This method tends to be less comfortable for the patient but is not usually considered painful. This method is not recommended for self-testing and should only be performed by a healthcare practitioner.
To read more about nasopharyngeal testing, check out the CDC’s infographic here.
A swab used for nasopharyngeal is one designed with a miniature tip made of an ultrafine flocked material and one with a thin, flexible handle usually made of polystyrene.
Great care has been taken by companies like Puritan to design swabs that prioritize efficient testing, optimizing getting as much specimen as possible while being mindful of patient comfort.
Which Swab Test is More Accurate?
The nasopharyngeal swabbing is generally the preferred method of specimen collection for COVID-19 testing. However, all methods are supported by the CDC. And a 2012 comparison study showed no significant statistical difference between the two methods for flu testing.
CDC recommends collecting and testing an upper respiratory specimen, such as nasopharyngeal, nasal mid-turbinate, or anterior nasal when using NAATs for confirmatory testing. In cases of discordant test results from different types of tests, results from laboratory-based NAATs should be prioritized over any POC or self-administered test. Source
Looking for more information on swab testing?
Check out our COVID-19 toolkit which outlines in detail how to perform both types of tests in an easily accessible PDF format.