How COVID-19 tests work

What you need to know about COVID-19 test

And what you need to know about Rapid Test Kits and Polymerase Chain Reaction Tests

Months into the pandemic, the world slowly eases into the new normal. With this, the need for testing is imperative. Biotech companies have already ramped up their production of test kits, but many still wonder how these tests work and they are effective.

Right now, there are two kinds of tests available. These are the rapid antibody test or rapid test kits (RTK) and Reverse Transcription Polymerase Chain Reaction (RT-PCR). How exactly different are they?

RTK and PCR: What’s the difference?

You can think of these as two categories. RTKs look into immunoassays or proteins that are linked to the virus. These proteins are either produced by the virus or by the body as a response to the virus. When the body identifies the presence of the virus, the immune system releases antibodies that then attach to it. This makes it possible to identify the virus as antibodies will bind to the antigens in the test. These tests are able to detect the virus on the eighth day of the onset of symptoms.

On the other hand, PCRs distinguish the genetic code of the virus itself. It uses a technique called reverse transcription-polymerase chain reaction wherein the medical technicians copy and enhance segments of the genetic code found in the sample to make it easier to detect. This test is most sensitive to the early days of infection.

In terms of specimen collection, RTKs just need a blood sample to detect the antibodies. Meanwhile, PCRs require samples taken from the nasal passages and the throat to identify if the presence of the virus itself.

For PCRs, the results are usually released within 24-48 hours. This time frame depends on the processing time of the laboratory. Samples should be taken to a Special Pathogens Laboratory (SPL) that’s a Biosafety Level 2+ facility. RTKs, on the other hand, are able to produce results in as little as 15 minutes. Both tests are now used by the government, healthcare facilities, and private institutions.

Direct comparison of PCR and RTK

A deeper look into RTKs

The ease of use, portability, and the quick results produced by RTKs make it a useful tool in detecting if the individual has been exposed to the virus and determining the best way to care for the patient. One example of an RTK available in the country now is the Wantai SARS-CoV Ab Rapid Test Kit, which identifies antibodies against COVID-19 in just 15 minutes. It has an accuracy of 98% when used on the eighth day of onset of the symptoms.

This test kit has been included in the World Health Organization’s Emergency Use Listing (EUL). Aside from that, it has secured the approval of the Food and Drug Administration (FDA) of the Philippines and Australia and has complied with the Special Certification of COVID-19 Diagnostic Kits. It is now available through GMT Manila.


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