Most Popular Sterile Nasopharyngeal Swabs Manufacturer Most Popular Sterile Nasopharyngeal swab, extend the cotton swab attached to the reagent into the nasal cavity, and scrape the mucosal epidermis several times with moderate force. With an oropharyngeal swab, extend the cotton swab attached to the reagent from the oral cavity into the pharynx, and scrape the mucosa of the bilateral pharyngeal …