The COVID-19 Antigen Rapid Test Device (Colloidal Gold) detects COVID-19 antigens through visual interpretation of colour development on the strip. COVID-19 antibodies are immobilized on the test region of the membrane respectively. During testing, the extracted specimen reacts with anti- COVID-19 antibodies conjugated to coloured particles and pre-coated onto the sample pad of the test. The mixture then migrates through the membrane by capillary action and interacts with reagents on the membrane. If there is sufficient COVID-19 antigens in the specimen, a coloured band will form at the according test region of the membrane. The presence of a coloured band in the test region indicates a positive result for the particular viral antigens, while its absence indicates a negative result. The appearance of a coloured band at the control region serves as a procedural control, indicating that the proper volume of specimen has been added and membrane wicking has occurred.