Laboratories all over the EU are working at full throttle. In the first week of November alone, they made over 11 million COVID-19 diagnostic tests. 

What exactly do we test? 

That depends on the type of test used. There are two main categories: 

• diagnostic tests – these detect the presence of the virus itself, either by looking for the virus’ genetic material or by looking for a specific protein from the virus. 
• antibody or serological tests – these check whether we have been exposed to the virus in the past. If we have antibodies that help the organism to fight the virus in our blood, this means we have already been infected by COVID-19. 

Which tests are the most important now? 

It's the diagnostic tests that are crucial to combatting the spread of the virus. Why? Because they diagnose an active infection.  

Where is the virus? 

The test samples are taken with a nasal or throat swab or a deeper nasopharyngeal (the part of the throat behind the nose) swab. For some tests, just a spot of saliva is sufficient.  

What exactly are we looking for in the samples?  

That again depends on the type of diagnostic test: 

• molecular tests detect the presence of the SARS-CoV-2 genetic code - ribonucleic acid (RNA) within the tested sample. They are also called RT-PCR or nucleic acid amplification tests (NAAT). This is the most reliable type of test. 
• antigen tests – detect the presence of specific proteins that are on the surface of the virus. They are more likely to miss an active infection in comparison to molecular tests.  

How long does it take to get the result? 

Up to a few days for the most sophisticated and accurate tests, but results of the fastest are available in as little as 15 minutes. Antigen tests provide quicker results and do not require a laboratory infrastructure, but they are less sensitive than PCR tests. 

How do the other tests work? 

Antibody or serological tests look for antibodies in our blood that are made by our immune system. Antibodies are our organism's response to the infection and can help overcome it. They develop a few days or weeks after an infection and stay in our blood for quite some time after recovery. So far, researchers are not yet sure if the presence of antibodies prevents re-infection. 

Why are they useful then? 

A positive result from an antibody test means you have had a COVID-19 infection but it doesn't tell you when. These tests cannot be used for diagnostics but are important source of information for scientists about the spread of the virus. 

Antibody tests can be done from a blood sample. The result is usually available the same day or within a few days (depending on the technique). 

What's the EU role?  

Since the beginning of the pandemic, the EU has done its best to coordinate the fight against COVID-19 despite the fact that each member state is largely responsible for its own health care system.

This is also true of testing. At this week’s video conference, European leaders discussed how to develop a common EU-approach for the use of rapid antigen tests, which are complementary to PCR testing. They also talked about national testing strategies and exchanged best practices. The countries will continue to work towards mutual recognition of tests and their results.

Any additional money for testing? 

The EU has already mobilised €100 million to purchase and deliver rapid antigen tests to member states. This will, for example, make it easier for people travelling between EU countries to be tested before departure or at their destination. 

Is testing coordinated at EU level? 

The EU is helping member states to make testing more efficient by recommending COVID-19 testing strategies. Hints are provided on how to prepare national and regional strategies such as how broad the testing should be, who should be tested first and what kind of tests should be used in certain conditions. All this will make testing more consistent across the EU and will enable researchers to draw more accurate conclusions from the results. 

Can I be sure that testing devices are reliable? 

Yes, you can, the EU is taking care of it for you. The European Commission's Joint Research Centre (JRC) created a database with detailed information on all publicly available equipment. A few hundred devices already bear the CE mark, which confirms that they meet the highest European standards and can be sold on the European market. This database helps those responsible for healthcare to choose the tests that are the most appropriate for the situation and needs in their country. If you are curious, you can browse the database; it is available on the JRC website.