The StrongStep® System Device for SARS-CoV-2 & Influenza A/B Combo Antigen Rapid Test employs chromatographic lateral flow test. There are three strips in the device that detect SARS-CoV-2, influenza type A and influenza type B respectively, Latex conjugated antibody (Latex-Ab) corresponding to SARS-CoV-2/Flu A/Flu B are dry-immobilized at the end of each nitrocellulose membrane strip. SARS-CoV-2/Flu A/Flu B antibodies are bond at the Test Zone (T) and Biotin-BSA are bond at the Control Zone (C) on each strip. When the sample is added, it migrates by capillary diffusion rehydrating the latex conjugate. If present in sample, SARS-CoV-2/Flu A/Flu B antigens will bind with the least conjugated antibodies forming