Viral proteins(8) Viral protein(8) Protein(8) Absolute quantification(6) Viral load(5) quantification(5) Ct values(5) high viral load(5) SARS-CoV-2 nucleocapsid(5) mass spectrometry(5) required(5) clinics(5) RT-qPCR(5) peptides(5) PRM(5) mass(5) heat(5) COVID-19(5) investigated(5) SARS-CoV-2 detection(5) Early detection(5) Clinical diagnosis(5) high resolution(5) positive patients(5) nasopharyngeal swab sample(5) pandemic(5) Nasopharyngeal swab(5) positive patient(5) Surveillance(5) speed(5)