A reagent is any substance or mixture of substances used to perform a laboratory test. Reagents may be liquid preparations or in solid form, such as test strips or other devices (e.g., glucose test strips for diabetics or devices for home pregnancy tests). Almost all medical laboratory testing is performed with ready-to-use reagents supplied by laboratory equipment manufacturers.
Two types of reagents are required to confirm the presence of the SARS-CoV-2 virus, responsible for COVID-19, in nasal and nasopharyngeal secretions. One reagent is used to isolate the viral RNA from other nucleic acids (human and bacterial) present in the sample. The other reagent contains the ingredients necessary to detect the viral RNA after amplification by nucleic acid amplification testing (NAAT) such as RT-PCR (polymerase chain reaction).