A nasopharyngeal swab is a device used for collecting a sample of nasal secretions from the back of the nose and throat.

This diagnostic method is commonly used in suspected cases of whooping cough, diphtheria, influenza, and various types of diseases caused by the coronavirus family of viruses, including SARS, MERS, and COVID-19.

[3][4][5][6][7][8] To collect the sample, the swab is inserted in the nostril and gently moved forward into the nasopharynx, a region of the pharynx that covers the roof of the mouth.

Rather than depending on a physical swab to catch material from the nasopharynx, aspiration uses a catheter that is attached to a syringe.

As with the swab method, the catheter is placed into the nostril and gently advanced to the nasopharynx, where approximately one to three milliliters of saline are introduced, followed by immediate re-aspiration of the saline—along with cells and secretions—back into the syringe.