Guidelines for in vitro tests for the diagnosis of COVID-19

Dr. Wolfgang Wodarg writes:

"It is a paper from the EU Commission that is very revealing in terms of the informative value of the tests currently used. . . . By the time there are clinically useful tests, we should all be tested, if possible. The federal government 'is currently planning a new comprehensive legislative package at a rapid pace to enable 4.5 million corona tests per week soon.' Even if clinically unusable, the test appears to be of great political importance."

I quote the following pertinent excerpts, with my emphasis (source here):

Official Journal of the European Union

COMMUNICATION FROM THE COMMISSION

Guidelines on COVID-19 in vitro diagnostic tests and their performance

(2020/C 122 I/01)

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4.   Considerations on test performance

      . . . .

The Commission, Member States and stakeholders should consider what are the critical aspects of device performance specific to COVID-19 on which a common approach should be taken.

For example, for RT-PCR tests, this could be the identification of stable target sequences (i.e. genetic fragments characteristic of SARS-CoV-2 virus to be detected). With every new patient infected, the virus may change (mutate) and these mutations in turn may render a particular test less effective, or even ineffective. It is therefore important that the mutation profile of the virus is monitored and that on that basis a particular RT-PCR approach is used. . . .

5.   Validation of test performance

As explained above, the manufacturer evaluates the performance of the device in accordance with the intended purpose before placing the device on the market.

However, especially given the rapid development of the pandemic, the performance of the device may vary in practice in comparison to the performance study the manufacturer has done for the purposes of CE-marking. Therefore, it is highly recommended to carry out additional validation of the clinical performance of tests for COVID-19 by comparison with a reference method in a sufficiently large number of target population subjects before introducing the devices into the clinical routine. Scientific peer-reviewed results for the clinical validation of commercial COVID-19 tests are highly recommended before they can be safely and reliably used for medical or public health decision making. Validation refers to confirmation that the test achieves the performance levels specified by the manufacturer.

       . . . .

Scarcity of reference methods and materials poses difficulties for these validation studies, and also for the evaluation of device performance by manufacturers. The Commission’s Joint Research Centre has recently developed a positive control material for RT-PCR tests which is available to laboratories in Europe. Seroconversion panels and positive sample panels are examples of further materials that are needed. Another issue currently is the lack of publicly available comparator data, which makes it difficult to compare the performance of devices. External quality assessment schemes could be one way to generate such data. The ECDC (4) and the WHO (17) are already in process of organising an external quality assessment scheme for RT-PCR tests.