Practical information about testing
Practical information about testing can be found at Government.nl . If you have symptoms, you can make an appointment to get tested. You can also be tested if you were in close contact with someone who tested positive for COVID-19, even if you do not have symptoms. There are also other exceptions in which testing without symptoms is possible. The same website also contains information about the test results.
Why is testing important?
It is important for people to get tested if they have symptoms. This ensures that new infections will be detected sooner. People who do turn out to have the virus will go into isolation and stay home. The Municipal Public Health Services (GGDs) then start source and contact tracing and recommend quarantine for household members and close contacts. This helps to prevent the person with COVID-19 and their close contacts from infecting others. Testing is important in order to curb and monitor the spread of the virus.
Vaccination, testing and measures
Once people have been vaccinated, the vaccine will protect them against the virus. However, a person who has been vaccinated must still keep following the measures, just like everyone else, until enough people in the Netherlands have been vaccinated. There are a number of reasons for this. The vaccines work well and are safe. However, there is a chance that you may become infected with the virus, even if you do not become ill from it. This possibility is still being investigated. We do not know yet if vaccinated people can still infect others. For that reason, it is important for everyone to comply with the measures for the time being.
Types of tests
There are various types of tests. Which types are there, and what do they tell us?
The PCR test
The PCR test detects specific fragments of genetic material from the coronavirus SARS-CoV-2. It is the most widely used and most reliable test. A smear is taken from the nose and throat with a cotton swab. This sample goes to a laboratory for the PCR test. The PCR test involves making copies of a small part of the virus. A small piece of genetic material from the virus is replicated repeatedly, in order to detect its presence. The PCR test has a high test sensitivity. That means that the PCR test also detects the virus in someone who is not carrying much of the virus yet, or no longer has much virus left in their body.
Testing for children
Children are usually tested with the same method as for adults: by taking a swab of the throat and nose. This type of test is often not very pleasant for children. Parents and caregivers are sometimes reluctant to have a child tested. Municipal Public Health Services (GGDs) focus extra attention on younger children who get tested. In the test lanes, for example, they take more time for the test. Some GGDs have a special test queue for children, or have employees who specialise in testing children.
In certain situations, a GGD may use a special swab equipped with a ‘saliva sponge’ to test children. In that case, the swab only needs to be inserted into the mouth to take a saliva sample. However, the collected saliva does not always yield enough usable material. In addition, these saliva tests must also be analysed separately.
Rapid PCR: LAMP test
The LAMP test (loop-mediated isothermal amplification) is a kind of PCR test, but the test is faster than most PCR tests. This test also works by replicating or copying a piece of genetic material. However, the LAMP test uses a different method than a ‘regular’ PCR test. The LAMP test requires different equipment and chemical substances than are needed for PCR tests. As a result, they can complement each other in this respect, rather than competing if supplies become scarce.
The antigen test
The antigen test detects the presence of antigens for SARS-CoV-2 in nasal and/or throat mucus. Antigens are pieces of the virus (proteins) that can produce an immune response in the body. If you are carrying the virus, the antigen test will quickly show that result – usually about fifteen minutes after applying the sample to the test set. The test can also be used outside a laboratory setting. The antigen test is less sensitive than the PCR test, especially if the level of virus particles is low. Someone who is not carrying much of the virus yet, or no longer has much virus left in their body, and is therefore not yet or no longer contagious, will often test negative on an antigen test. In that case, a person may wrongly get a negative test result, even if they may have COVID-19, or had it in the past.
The serological test determines if there are specific antibodies against the coronavirus SARS-CoV-2 in your blood. The test shows if you have had the virus. Antibodies are part of your natural defences: the immune system. The body produces them in response to an infection with the virus. It can take 2 to 3 weeks for your body to produce the right antibodies and release them in sufficient quantities in your blood, so they can be detected. A serological test involves taking a blood sample. This test is primarily used for research and screening at the population level, by selected laboratories.
The PCR test and the antigen test are tests that have been used in medical laboratories for many years to detect the presence of other diseases. Tests for COVID-19 are also being developed that are based on less frequently used principles. One of those tests is the ‘breath test’, also known as the electronic nose. Exhaled air is examined for molecules that indicate that you are infected with the virus. This test is mainly suitable for excluding the possibility that you are currently carrying the virus. A second, different test, such as a PCR or antigen test, is needed to detect the presence of the coronavirus SARS-CoV-2. Research is now being done to determine how good that test is for people who do not have symptoms and where it could be used.
When should each type of test be used?
As other types of testing become available, it is important to take a close look at how and when certain tests can be used in practice. Each test has its advantages and disadvantages, such as the speed of the result, the place where the test can be done (inside or outside a laboratory) and the sensitivity of the test. In certain situations, a false-negative result can have serious consequences. Examples include people who are seriously ill as well as vulnerable people in institutions. In such cases, it is important to use a test that is as accurate as possible. The PCR test is the best option for this purpose. The PCR is the ‘gold standard’, and the LAMP-PCR is considered equivalent.
In situations where the disadvantage of a false-negative test result outweighs, for example, speed and flexibility, less accurate tests can also be used. Like the antigen test. The breath test is a test that can be used as pre-selection; if the test is positive for COVID-19, it is important to always use a second test to confirm.
The Outbreak Management Team advises the Cabinet about which individuals or groups can be tested with which type(s) of test. A clear table shows which test could be used in different situations.
Testing with and without symptoms
In general, the results of each test are more reliable when you have just developed symptoms. From 1 December on, people who do not have symptoms can also get tested during their quarantine period from day 5 on.
In 2021, the Cabinet wants to start using larger-scale and more frequent testing, including people without symptoms. The aim is to create more opportunities to open up society, while at the same time maintaining a good view on the virus and its spread. The Outbreak Management Team will be advising the Cabinet on this matter.
The role for RIVMNational Institute for Public Health and the Environment in testing
RIVM draws up the guidelines and protocols for testing and for source and contact tracing in cooperation with the professional field. The Municipal Public Health Services (GGDs) and hospitals carry out the tests. The quality of the tests being offered is monitored closely. RIVM is also researching various aspects of the SARS-CoV-2 virus and the disease COVID-19. For example, RIVM is researching various types of tests and compiling data from various studies being conducted by other Dutch laboratories, combining the data so that the laboratories can learn from each other and make well-informed choices regarding certain tests. RIVM is currently researching such topics as which antigen and antibody tests yield the most reliable results, and how well you are protected after having COVID-19. It is not yet known how long antibodies against the virus remain present in the body. So far, it has been confirmed that a limited number of people have been infected for a second time.
WHO Reference Laboratory
RIVM is a WHO reference laboratory and develops various diagnostic tests for the coronavirus SARS-CoV-2. These diagnostic tests are checked along with international partners. The techniques are then rolled out to laboratories at home and abroad. The labs report the results of quality assessments to RIVM. RIVM looks at how a lab operates compared to other laboratories.
Testing capacity in the Netherlands
The Dutch Government, together with the Municipal Health Service (GGD) and the National Coordination Team Diagnostic Chain (LCDK), ensures that there are enough test sites, test materials and laboratories that can test for the coronavirus SARS-CoV-2.