The Difference between PCR, Antigen, and Antibody Tests
| PCR Test | Antigen Test | Antibody Test | |
|---|---|---|---|
| Concept | SARS-CoV-2 has genetic material in the form of RNA. Presence of COVID-19 specific viral RNA from patient samples indicate that the patient is SARS-CoV-2 infected. | Antigens are present on the surface of the virus. Presence of COVID-19-specific antigen in patient samples indicate that the patient is SARS-CoV-2 infected. | Production of antibodies are triggered after COVID-19 infection. Status of infection can be confirmed by detecting the presence of IgM or IgG antibodies in patient blood samples. |
| Testing Principle | PCR tests amplify and detect targeted region of SARS-CoV-2 genetic material. | Antigen tests detect SARS-CoV-2 antigen in patient samples. | Antibody tests detect IgM and IgG antibodies targeting SARS-CoV-2 in patient samples. |
| Sample Type | Nasal, nasopharyngeal swab, oropharyngeal swab, deep throat saliva | Nasal, nasopharyngeal swab, oropharyngeal swab | Blood (Whole blood, plasma, serum) |
| Biomarker | SARS-CoV-2 virus | SARS-CoV-2 antigen | SARS-CoV-2 IgM and IgG antibodies |
| Suitable period for use | From onset of infection | From 2 days after infection | From 7 days after infection |
Operation | 4-6 hours | Around 20 minutes | Around 20 minutes |
| Operation Requirements | Professional medical operator and lab equipment | No professional operator or equipment required | No professional operator or equipment required |