Early development of self‐administered COVID‐19 rapid test based on nucleocapsid detection in saliva sample

More than 6,000,000 people have died due to the coronavirus (COVID‐19) pandemic. This disease spread quickly its highly contagious nature. The SARS‐CoV‐2 virus that causes can be transmitted through saliva droplets secreted by infected at a distance of less 1 m. As result, has been accepted as an alternative specimen for COVID‐19 detection Centers Disease Control and Prevention (CDC). Furthermore, WHO recommended use rapid antigen tests based on lateral flow immunoassay when reverse transcription‐polymerase chain reaction (RT‐PCR) is not available. We developed saliva‐based test optimizing antibody concentration optimum pH conjugation gold nanoparticles. found best running buffer formulation consisted 75 mM sodium phosphate buffer, 1% NaCl, Triton X‐100, 0.5% N‐acetyl‐L‐cysteine, 0.02% azide. addition mucolytic agent in reduce viscosity saliva, thus improving sensitivity. detected lowest nucleocapsid protein 0.1 μg/mL. Our study revealed 100% specificity against negative no cross‐reaction with avian influenza hemagglutinin.