Swab or blood test?
After all, what options are there for testing Covid-19 and which is the most suitable for each situation?
One of the World Health Organization’s (WHO) most important recommendations in the fight against the pandemic has been “test, test, test!”. It is therefore important that you know what options are currently available and what is expected to be available in the future.
Tests that detect the virus (PCR test)
The PCR test is carried out using a swab that takes a sample of nasal product and/or the back of the throat.
This test is currently the only proven way of knowing whether or not you have the virus active in your body. The great advantage of these tests is their high sensitivity and specificity, which makes them the preferred method.
However, with this solution it is difficult to scale up testing on a large scale.
Tests that confirm the presence of immunity (serologies)
There are also serologies, either by venipuncture or by finger prick, with finger prick tests also being known as “rapid tests”.
These tests make it possible to see if there is immunity – if there is, it means that there has been contact with the virus.
After this contact, the body develops defenses, antibodies, which can be of 2 types: IgM or IgG.
IgM are antibodies from recent immunity – if an IgM test is positive, a PCR test should be carried out next.
IgG are antibodies of delayed immunity – we don’t know if IgG immunity is definitive.
Tests in development
With the need to move towards simpler, large-scale testing, there has been an increase in research and the development of more tests.
The American company Sherlock Biosciences, linked to Harvard University, is developing a type of test that allows the virus to be detected at room temperature, without the need for a laboratory.
However, these tests have not yet been approved in Portugal.
The UK also started using Covid-19 diagnostic tests at the beginning of August, which promise to reduce the waiting time for results from 24 hours to 90 minutes.
The unique thing about these tests is that as well as detecting Covid-19, they can also detect the flu virus – which could prove particularly useful for making more accurate diagnoses in winter.
As new solutions are recognized by the Directorate-General for Health in Portugal, we will make them known to all our partners and clients.
