Three methods of Covid-19 detection

After the emergence of Covid-19, it has spread very quickly across the world. On February 28, the WHO raised the global risk level of new coronary pneumonia to "very high". Fast, accurate, and simple detection methods are more important. Currently, what are the current detection methods for the Covid-19? How effective?

There are usually two strategies for detecting infectious diseases: detecting the pathogen itself or detecting the antibodies produced by the human body to resist the pathogen. Detection of pathogens can detect antigens (usually pathogen surface proteins, some use internal nuclear proteins), and nucleic acids(RT-PCR) can also be detected. If any one of nucleic acid, antibody, or antigen is detected in the body fluid of the patient, it means that it has been infected.

Antigen test: Detect the antigen of the virus, indicating the active viral infection.

RT-PCR test: Detect the RNA of the virus, indicating the active viral infection.

Antibody test: Detect the antibody generated by the immune response after a viral infection, indicating the active or past viral infection. 

What are the characteristics of the three detection methods?

Nucleic acid(RT-PCR) detection: high requirements for a laboratory environment, testing personnel, equipment, etc., high detection sensitivity and good specificity, usually results in 2-3 hours.

Antibody detection: Invasive sampling, simple and convenient operation, suitable for the detection of a large number of suspected cases and asymptomatic infections, the fastest results are available within 15 minutes.

Antigen detection: non-invasive sampling, low requirements for the laboratory, can be used for early screening, early diagnosis, suitable for large-scale screening in primary hospitals, the fastest results within 15 minutes.

Currently, nucleic acid detection is widely used, and the sensitivity and specificity of antibody/antigen detection reagents are still limited. Nucleic acid/antibody/antigen detection has its own focus and cannot be substituted for each other. The combined application of multiple detection methods can effectively shorten the detection window and increase the positive detection rate.