The Difference between PCR, Antigen, and Antibody Tests

PCR TestAntigen TestAntibody Test
ConceptSARS-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 PrinciplePCR 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 TypeNasal, nasopharyngeal swab, oropharyngeal swab, deep throat salivaNasal, nasopharyngeal swab, oropharyngeal swabBlood (Whole blood, plasma, serum)
BiomarkerSARS-CoV-2 virusSARS-CoV-2 antigenSARS-CoV-2 IgM and IgG antibodies
Suitable period for useFrom onset of infectionFrom 2 days after infectionFrom 7 days after infection


4-6 hoursAround 20 minutesAround 20 minutes
Operation RequirementsProfessional medical operator and lab equipmentNo professional operator or equipment requiredNo professional operator or equipment required