In a long video denying the validity of Covid-19 PCR tests, it's stated at one point (15:17), without much context that

the European court declaring that Covid-19 tests are "not fit for purpose"

The previous minutes don't mention any particular court or lawsuit, so it's hard to tell what "the European court" might refer to. (The video is a wee bit of a Gish gallop in parts.)

So did any European court declare Covid-19 PCR tests "not fit for purpose"? And does that lawsuit have much bearing on Europe as whole?

  • 1
    Perhaps this: Covid PCR test reliability doubtful – Portugal judges?
    – Hulk
    Commented Jan 18, 2021 at 12:46
  • @Hulk the judges conclude that “the probability of a person receiving a false positive is 97% or higher”.. Seriously? Courts have made bad decisions, but this ranks right up there. The COVID-19 PCR test is designed to have an extremely low false positive rate, at the expense of a not quite so low false negative rate. Commented Jan 18, 2021 at 14:33
  • @DavidHammen: yeah that struck me too, but they talk of high CT (threshold) causing that outcome, not PCR in general. While they misunderstood some of the science, they didn't quite flip it on its head. Also that claim doesn't appear in the judgement linked by LangLang, so maybe it's in some other court document. Maybe the court published a longer argument besides that summary that LangLang linked. Commented Jan 18, 2021 at 14:36
  • @DavidHammen: what I find more strange from a legal point of view is that suspicion of infection is seemingly not enough to keep someone in quarantine in Portugal. It is sufficient in most other countries. Commented Jan 18, 2021 at 14:42
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    @Fizz: The claim does appear in the second link (search for "97%"). May be worth its own question. (Just to be clear: I think the claim is P(healthy | positive result) = 0.97, NOT P(positive result | healthy) = 0.97, with an assumption of 3% prevalence of the virus in those tested)
    – Oddthinking
    Commented Jan 19, 2021 at 1:04

1 Answer 1



A Portuguese court found the isolated use of nothing but a PCR-test is 'not fit for purpose'.

The purpose here being the ordered quarantine of those merely 'tested positive'.

The court concluded that a PCR test alone was insufficient to diagnose the illness or to determine infectivity of any person tested, and was insufficient grounds for forced isolation of individuals. The court required the diagnosis of a qualified medical doctor on top of the results by the PCR test.

Detaining individuals on the results of a (possibly non-specific) PCR test was therefore seen as illegal in Portugal.

Note: it is quite the point to observe which purpose 'the' PCR-test was found to be unfit for: diagnosis for the purpose of forced detainment. Further, the initial act complained against resulted in detention of close contacts to 'a PCR-positive person'.

The ruling is found summarised here:

PROCESSO N.º 1783/20.7T8PDL.L1-3 covid Tribunal da Relação de Lisboa Data 11 de novembro de 2020

Descritores Habeas corpus Interesse em agir SARS-CoV-2 Testes RT-PCR Privação da liberdade Detenção ilegal


I. The ARS cannot appeal against a decision ordering the immediate release of four persons for illegal detention in the context of a habeas corpus procedure (art. 220 als. c) and d) of the C.P.Criminal), requesting that the compulsory confinement of the applicants be validated because they are carriers of the SARS-CoV-2 virus (A....) and because they are under active surveillance for high-risk exposure decreed by the health authorities (B..., C.... and D.....) because they have no legitimacy or interest in acting.

II. The application was also dismissed as manifestly unfounded:

A. Prescription and diagnosis are medical acts for which a doctor is exclusively responsible and which are registered with the Medical Association (Regulation No 698/2019 of 5.9).

Thus, the prescription of diagnostic aids (such as tests for the detection of viral infection), as well as the diagnosis of the existence of an illness, in relation to each and every person, is a matter which cannot be carried out by law, resolution, decree, regulation or any other normative means, as these are acts which our legal system reserves to the exclusive competence of a doctor, it being certain that the latter, in advising his patient, should always seek to obtain his informed consent (Article 6(1) of the Universal Declaration on Bioethics and Human Rights).

B. In the case in question, there is no indication or proof that such a diagnosis has actually been made by a qualified professional under the terms of the Law and who has acted in accordance with good medical practice. In fact, what emerges from the facts given as evidence is that none of the applicants has even been seen by a doctor, which is frankly inexplicable, given the alleged seriousness of the infection.

C. The only element in the proven facts in this respect is the carrying out of RT-PCR tests, one of which showed a positive result for one of the applicants.

D. In the light of the current scientific evidence, that test alone is incapable of establishing beyond reasonable doubt that such a positive result in fact corresponds to a person's infection with the SARS-CoV-2 virus, for a number of reasons, including two (in addition to the question of the gold standard which, because of its specific nature, we will not even address): This reliability depends on the number of cycles that make up the test; Because this reliability depends on the amount of viral load present.

III. Any diagnosis or any act of health surveillance (such as the determination of the existence of viral infection and high risk of exposure, which are covered by these concepts) made without prior medical observation to the patients and without the intervention of a doctor registered with OM (who would evaluate their signs and symptoms, as well as the examinations that he considered appropriate to their condition), violates Regulation No. 6/2002. 698/2019, of 5.9, as well as the provisions of article 97 of the Statute of the Order of Physicians, being liable to constitute the crime of usurpation of functions, p. and p. by article 358 al.b), of the Criminal Code.

IV. Any person or entity issuing an order, the content of which is extended to the deprivation of physical liberty, on an out-patient basis, of others (whatever nomenclature this order may be called: confinement, isolation, quarantine, prophylactic custody, health surveillance, etc.), which does not comply with the legal provisions, namely the provisions of art. 27 of the CRP, will be making an illegal arrest, because it is ordered by an incompetent entity and because it is motivated by a fact for which the law does not allow it. (Summary prepared by the rapporteur)

The full 34 pages are to be read here.

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    Interesting. The issue however it that being "seen" by a doctor is probably irrelevant & pointless if someone is asymptomatic. I guess Portugal would have never confined Typhoid Mary. The article that Huk linked under my q has such criticism of the court's decision. Commented Jan 18, 2021 at 13:32
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    The third paragraph was an expression of your personal value system, phrased as an ad hominem attack against people who disagree with you. Edited.
    – Oddthinking
    Commented Jan 19, 2021 at 0:48
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    I think this answer could be improved by emphasizing the "Note" paragraph. Context is important here. The court was not determining whether PCR tests "work". The court was determining whether PCR tests alone are enough to meet the highest standard of proof that exists in pretty much any legal system, namely the standard of proof required for the government to (temporarily) take away someone's Basic Human Rights (in this case, forced detainment without a trial). That is an extremely high standard of proof, and being ineffective for this specific purpose does not necessarily … Commented Jan 19, 2021 at 6:35
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    … translate to other purposes or circumstances. Commented Jan 19, 2021 at 6:35
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    Then again, "a Portuguese court" is not the same as "the European court" Commented Jan 20, 2021 at 9:30

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