COVID-19 Tests: NAT Test­ing is Con­sid­ered the Gold Stan­dard

NAT tests are currently the most reliable COVID 19 tests for diagnosing infections with the new coronavirus SARS-CoV-2. NAT stands for Nucleic Acid Amplification Technique. This includes the PCR method (Polymerase Chain Reaction, PCR) developed by a working group at the Charité in Berlin, which can be used to directly detect the SARS-CoV-2 virus in infected persons on the basis of a throat swab.

Eppendorf Vessel (Source: A.Buck/Paul-Ehrlich-Institut)

In addition, there are currently so-called rapid tests, which patients can also perform themselves. Most rapid tests detect antibodies against COVID-19. After a SARS-CoV-2 virus infection, antibodies are usually only detectable 7 to 14 days after the onset of the disease. Other rapid tests serve the direct detection on the basis of the recognition of protein components of the virus (virus antigen). These rapid tests are still in development.

All COVID-19 tests are subject to the EU directive on in vitro diagnostic devices (IVD), which currently governs the marketing authorisation of IVDs in Europe. According to this directive, manufacturers can still certify COVID-19 tests - as "low-risk IVDs" - themselves and waive independent review of the tests before they are marketed. From the point of view of the Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines, the validation of the tests, which are offered on the internet and in pharmacies, is therefore not assured. It has been proven that there are also counterfeits.

Under the future IVD regulation, which must be implemented from May 2022, an EU reference laboratory and a Notified Body must be involved, as the COVID 19 tests will then most likely be in the highest risk category. This will require a laboratory examination of the tests and independent verification of the data. The Paul-Ehrlich-Institut is preparing to make an application to become one of the EU reference laboratories.

Updated: 23.03.2020