The vast majority of the laboratories analysing COVID-19 tests are performing at the very highest standard of quality. This has become apparent from the first nationwide external quality assessment (EQA) of diagnostics used in laboratories for COVID-19 testing. The results are presented in the report ‘External Quality Assessment of Laboratories Performing SARS-CoV-2 Diagnostics for the Dutch Population’. 

The Netherlands has an extensive network of 72 laboratories working on SARS-CoV-2 diagnostics. They examine the samples from the COVID-19 tests to check for the genetic material from the virus. They do this with a PCR test or another, similar test. The tests used by the laboratories are constantly subjected to quality checks by RIVMNational Institute for Public Health and the Environment and Erasmus MC. RIVM and Erasmus MC are the two WHO reference labs for COVID-19 in the Netherlands. The tests that the laboratories use have to meet requirements in terms of detecting the virus (sensitivity) and providing an accurate result (specificity). Now, for the first time, a nationwide quality assessment was conducted, covering 93% of the laboratories affiliated in November 2020.

Structure and results   

The quality of SARS-CoV-2 diagnostics in the Netherlands was assessed using sets of 10 different prepared samples. Some of these “simulated clinical specimens” contained heat-inactivated SARS-CoV-2 virus in varying amounts, while others contained other respiratory viruses or their genetic material. The laboratories participating in the assessment were asked to use their own methods (workflows) to examine these samples for the presence of SARS-CoV-2.

The vast majority of the laboratories are performing at maximum quality. In total, the laboratories collectively used 164 different methods (workflows) to detect SARS-CoV-2. Laboratories often use the same methods. Despite all these different methods, nearly all the laboratories were in fact able to detect find the genetic material of the virus in the samples from which the assessment researchers expected it to be found, using the majority of methods. Some of the methods used performed slightly less well, falling just short of the highest possible score. This was often because these methods are not quite able to detect the very lowest concentration of SARS-CoV-2 in a sample.

The laboratories and the methods they use are subject to very high standards. RIVM provides ongoing support to the laboratories, by giving advice and by making samples available so that all the methods used can achieve the very highest standard.

The results of the assessment will be presented to the Ministry of Health, Welfare and Sport (VWS). RIVM will also be sharing the results with the WHO and the ECDC. Other countries are also conducting similar assessments, and are also sharing their results.  By doing so, we learn from each other and facilitate excellent diagnostics.