A nasal swab is a medical test used to collect samples from the inside of the nose. This procedure typically involves using a long, thin cotton swab to gently scrape the nasal passages. It is commonly used to test for infections, such as COVID-19, influenza, or strep throat. The collected sample is then sent to a laboratory for analysis. Results can help diagnose illnesses and determine the appropriate treatment. Nasal swabs are generally quick and can be performed in various settings, including hospitals, clinics, and testing sites.