RT-PCR and antibody tests are needed to ultimately fight COVID-19. They are, however, for very different uses and should not be confused with one another.
RT-PCR is a laboratory test and is the global gold standard for detecting current infections of SARS-CoV-2 - the coronavirus that causes COVID-19.
Serology antibody rapid tests are either a laboratory test or a finger-prick rapid test that uses your blood as the specimen type. Antibodies are generated by our immune system when we have contracted a virus. As there are individuals who may have contracted SARS-CoV-2 - but with no or only have mild symptoms - antibody testing can tell if you have been previously infected as antibodies for the said-virus would be in your system. Therefore, if the RT-PCR of the deep throat saliva shows the presence of the virus, it can be concluded that a patient is COVID-19 positive (and therefore infected). However, the antibody test of the same patient will most likely be negative, as COVID-19 antibodies take a duration of 5-8 days to be in sufficient quantities and to be detected.
Additionally, the WHO has also recently published statements
with regards to the different types of testing.
While antibody tests can be valuable, COVID-19 antibody testing hasn’t been fully tested yet to ensure reliability, which is why guidelines set specifically for Hong Kong regarding COVID-19 recommends only RT-PCR testing in the detection of COVID-19.
WHO does not currently recommend the use of antigen-detecting rapid diagnostic tests for patient care, although research into their performance and potential diagnostic utility is highly encouraged.
WHO does not recommend the use of antibody-detecting rapid diagnostic tests for patient care but encourages the continuation of work to establish their usefulness in disease surveillance and epidemiologic research.