Specificity: Specific for the nucleocapsid of Covid-19 virus. Cross reacts with SARS. Non-reactive with: Influenza A, Influenza B, Adenovirus & MERS. Reactive with the nucleocapsids of Variants: UK B.1.1.7, SA B.1.351, Brazil P.1, B.1.617.2 (Delta), B.1.