Can antigen testing be performed using a throat swab?

Antigen testing can generally be performed using throat swabs, but nasal swabs are primarily used.

Antigen testing is a relatively convenient diagnostic method. Common applications include self-administered SARS-CoV-2 antigen tests, lymphocyte differentiation antigen assays, and hepatitis B surface antigen/antibody tests. Among these, self-administered SARS-CoV-2 antigen testing is most frequently used and typically employs nasal swabs. Although throat swabs may be collected, they are rarely used in practice. It is recommended to follow the manufacturer’s instructions, which generally specify nasal sampling as the preferred method. This is because nasal specimens typically yield higher viral loads than throat specimens, resulting in greater test accuracy and reliability. Furthermore, collecting throat samples requires mouth opening, which increases the risk of infection transmission and poses potential health risks.

The collection procedure involves inserting the swab 1–1.5 cm into the nasal passage and rotating it gently against both sides of the nasal cavity for approximately four full turns. Prior to sampling, excess nasal mucus may be cleared; however, nasal irrigation with saline should be avoided, as it may dilute the viral concentration in the nasal cavity and compromise test accuracy. Sampling and testing must be conducted in a clean environment to prevent environmental contamination of the test reagents, which could affect results. Additionally, the swab must reach the standard depth within the nasal cavity to collect epithelial cells and exfoliated cells from the mucosal surface—ensuring an adequate and representative sample.