A nasopharyngeal swab is a medical procedure used to collect a sample from the back of the nose and throat. This test is commonly performed to diagnose respiratory infections, including those caused by viruses like COVID-19 or bacteria such as Streptococcus pneumoniae. A healthcare professional uses a long, flexible swab to gently reach the nasopharynx, which is located above the soft palate. The collected sample is then sent to a laboratory for analysis. Results can help determine the presence of infections and guide appropriate treatment. Nasopharyngeal swabs are generally quick and safe, though some patients may experience mild discomfort during the procedure.