SARS-CoV-2 (COVID-19) serology: implications for clinical practice, laboratory medicine and public health

• Published in: Canadian Medical Association journal (CMAJ) 2020-08, Vol.192 (34), p.E973-E979
• Main Authors: Van Caeseele, Paul, Bailey, Dana, Forgie, Sarah E, Dingle, Tanis C, Krajden, Mel
• Format: Article
• Language: English
• Subjects: Betacoronavirus; Clinical Laboratory Techniques; Communicable Disease Control; Coronavirus Infections - diagnosis; Coronavirus Infections - epidemiology; Coronavirus Infections - prevention & control; Coronaviruses; COVID-19; COVID-19 Testing; Humans; Laboratories; Middle East respiratory syndrome; Pandemics - prevention & control; Pneumonia, Viral - diagnosis; Pneumonia, Viral - epidemiology; Pneumonia, Viral - prevention & control; Public health; Review; SARS-CoV-2; Sensitivity and Specificity; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2
• ISSN: 0820-3946; 1488-2329; 1488-2329
• DOI: 10.1503/cmaj.201588

Clinical presentation in persons infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ranges from asymptomatic to the life-threatening respiratory distress that can occur with coronavirus disease 2019 (COVID-19). Diagnosis of acute or new cases of SARS-CoV-2 infection at present relies upon molecular-based detection of viral RNA in upper or lower respiratory tract specimens, typically within 2-7 days after exposure. In this period, active viral shedding occurs, and individuals who are infected can transmit the virus to others. Although viral RNA may still be detected in respiratory and stool specimens of some people for many weeks after they have recovered, this does not appear to pose a transmission risk. Serological testing involves detection of antibodies specific to SARS-CoV-2 infection in blood, serum or plasma. The role of serology is limited in the diagnosis of acute COVID-19 because it usually takes a minimum of 7-14 days or more after symptom onset to develop a reliable and measurable SARS-CoV-2 antibody response. However, interest has arisen in the potential application of serological testing for purposes as wide-ranging as authorization of international travel, stratification of reinfection risk in workplaces and the reduction of public anxiety to facilitate resumption of economic activity.