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 virus levels are low, the antigen test will often give a negative result. At the very beginning of the infection, virus levels in the body are still low, but it is still possible for the person to test positive after that. Virus levels decrease again later in the infection, and the person will no longer be contagious by that point. In that case, a person may wrongly get a negative test result, even if they may still have COVID-19, or had it in the past.

Application in practice

Laboratories, hospitals, Municipal Public Health Services (GGDs) and RIVMNational Institute for Public Health and the Environment are working closely on researching various antigen tests with the PCR test. RIVM also compiles national and international research on this topic. The aim is to gather information and to see how the antigen test can be used more often in practice. For example for people who do not have any symptoms, have not developed symptoms yet, or only have mild symptoms, and whose virus levels are low.

The Outbreak Management Team advises the Cabinet about which individuals or groups can be tested with which type(s) of test. The OMT also advises on the possible use of antigen tests. A clear table shows which test could be used in different situations.

 

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. 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.

Although more testing can be done using approved antigen tests, there are also challenges. The test does give a quick result, but each test must be performed individually by a lab technician or other trained person. In contrast, a single lab technician can process many PCR tests at the same time, which can then be completed by automated equipment. In one day, a single lab technician can perform many more PCR tests than antigen tests.     On the other hand, antigen tests are less technically complicated to perform than PCR tests, and require far less equipment and complex devices. Moreover, they can also be used outside a laboratory setting.

The antigen test is offered in some (XL) GGD test lanes. There are also organisations that take the initiative to test their personnel for COVID-19 using a rapid antigen test. To ensure clarity about mandatory requirements for testing  , principles   have been drafted for testing for COVID-19 outside the GGD test lanes, and the Inspectorate for Health Care and Youth (IGJ) supervises such testing.