Factors causing serological results to outnumber PCR -based testing results |
l PCR-related–leading to underestimation of cases ○ Sample collection, transport, storage, and processing. ○ Reduced viral load in asymptomatic cases. ○ Focus of infection not always nasopharynx, in many cases lungs. ○ Population under -testing l Serological ○ Immune response sensitive (when tested with confirmed cases) and specific (when tested on pre-COVID-19 sera). ○ The presence of antibodies indicates current or past exposure, whereas PCR testing may only indicate current infection. ○ The load threshold for antibody production may be much lower than that required for PCR testing to be positive. |