Comparison of three detection methods

Comparison of three detection methods


According to the research data of SARS, the positive rate of nucleic acid detection in the early 1-5 days is less than 50%, while the antibody detection rate is about 20%, and the antigen detection of positive rate is 90%.
 
(1) Antigen test VS. Nucleic acid test
 
Detection Substance: Antigen detection, Nucleic acid detection both directly detects part of the virus, the result is used as direct evidence of infection of novel coronavirus.
 
Detection Time: Antigen detection costs less time which takes only 15 minutes, while Nucleic acid test takes 4-6 hours or more.
 
Application stage: Antigen detection, nucleic acid detection can be applied in the early stage of the disease (1-5 days after developing symptoms, or even in the incubation period) to obtain positive results.
 
Test conditions: Antigen test is convenient and fast, no special equipment required, visual interpretation; Nucleic acid test requires complex instruments, which requires professionals to operate and high biosafety level of the laboratory.
 
Application Scenario: Nucleic acid detection requires a high degree of laboratory environment and operators; and the detection cycle is long with low efficiency, which takes average 5-6 hours to obtain results. Antigen detection has no special requirements on the detection environment and detection personnel. It is simple and quick, and the results can be obtained in 15 minutes.
 
Antigen detection can be used in the early course of the disease, especially for monitoring key population. When there are no nucleic acid detection conditions, Antigen detection could be used preferred, the early detection the early intervention, conducive to epidemic control.


                                                          Sandwich ELISA                                                                IgM or IgG Capture ELISA
 
Detection Substance: The antigen detection detects the novel coronavirus N protein antigen, which can be used as direct evidence of viral infection. Antibody is produced when the immune responses for the human body to be infected with the virus, so the Antibody test is the indirect evidence of viral infection.
 
Detection Time: Both are rapid detection reagent, which takes about 15 minutes.
 
Application stage: Antigen detection can be applied in the early stage of the disease (1-5 days after developing symptoms, or even in the incubation period) to obtain positive results. There is a time lag for Antibody test, 5-7 days after developing symptoms can be detected, which is more suitable for detection in the late course of disease.
 
Test conditions: Antigen test is convenient and fast, no special equipment required, visual interpretation; Nucleic acid test requires complex instruments, which requires professionals to operate and high biosafety level of the laboratory.
 
Comparison of detection principles: Antigen detection uses double antibody sandwich method, its detection specificity is based on the recognition of two antibodies to the antigen, which greatly reduces the probability of recognition error, the detection is basically not affected by other viruses, false positive cases are less.