The Difference between PCR, Antigen, and Antibody Tests

PCR Tests
Antigen Tests
Antibody Tests
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 SARS-CoV-2 virussamples 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)
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  Time
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