More About COVID-19 Tests


The Difference between Rapid Antigen, 

Rapid Antibody and PCR Tests



 Rapid Antigen Tests
 Rapid Antibody Tests
 PCR Tests
Concept
 Antigens are present on the surface of the virus. Presence of COVID-19 specific antigen in patient SARS-CoV-2 virus 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.
 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. 
Testing Principle
 Antigen tests detect SARS-CoV-2 antigen in patient samples.
 Antibody tests detect IgM and IgG antibodies targeting SARS-CoV-2 in patient samples. 
 PCR tests amplify and detect targeted region of SARS-CoV-2 genetic material.
Sample Type
 Nasal, nasopharyngeal swab, oropharyngeal swab
 Blood (Whole blood, plasma, serum)
 Nasal, nasopharyngeal swab, oropharyngeal swab, deep throat saliva
Biomarker
 SARS-CoV-2 antigen
 SARS-CoV-2 IgM and IgG antibodies
 SARS-CoV-2 virus
Suitable period for use
 From 2 days after infection
 From 7 days after infection 
 From onset of infection
Operation  Time
 Around 20 minutes
 Around 20 minutes
 4-6 hours
Operation Requirements
 No professional operator or equipment required
 No professional operator or equipment required
 Professional medical operator and lab equipment 


Comparison of Different Sampling Methods for

COVID-19 Tests



 Nasal swab Nasopharyngeal swab
 Oropharyngeal swab
 Deep throat saliva
 Blood (Whole blood,plasma, serum)
Sampling Method Collection of
nasal mucosal secretions and tissues
from the nostrils.

Test Target: SARS-CoV-2 antigen, viral RNA 		Collection of nasopharyngeal secretions from the
nasopharynx, which is located at base of our skull and roof of the mouth.

Test Target: Viral RNA 		Collection of secretions and tissues from throat and tonsil.

Test target: Viral RNA 		Collection of secretions from the throat and tonsil through saliva.

Users cannot eat, drink, use mouthwash or brush their
 teeth within 2 hours before specimen collection

Test target: Viral RNA 		Collection of venous or fingertip whole blood

Test target:  SARS-CoV-2 antibodies
Advantages
 Sampling method can be used for self-tests.

Users will only need to insert the swab 2.5cm into the nostrils.

No discomfort feeling
 Sampling method can produce higher sample quality
 Less discomfort feeling
 Sampling method can be used
 for self-test

Easy to use

No discomfort feeling
 Sampling method allows user to analyse the presence of different types of antibodies
Disadvantages Potential self-collection error

Not suitable for children under 6		 Strong discomfort feeling

Require trained professional to operate

Not suitable for children under 6
 Require trained professional to operate

Typically used in conjecture with nasal swab sample collection

Not suitable for children under 6
 Require specific sampling requirements to be met
e.g. No eating or drinking, use of mouthwash and brushing teeth within 2 hours before specimen collection

 Invasive sampling process

Cannot directly detect the presence of SAR-CoV-2 virus