Nasal swab: Using a flocked or spun polyester swab, insert the swab at least 1 cm (0.5 inch) inside the nostril (naris) and firmly sample the nasal membrane by rotating the swab and leaving in place for 10 to 15 seconds.

- https://ldh.la.gov/assets/oph/Center-PHCH/Center-CH/infectio...

Nasopharyngeal Swab vs Nasal Swab: Comparing Methods

https://blog.puritanmedproducts.com › nasopharyngeal-...
Oct 14, 2021 — 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.

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.