Ever since the COVID pandemic began, there has been a lot of misinformation, lies and myths spread about PCR testing. First of all, it is important to realise that people make money from spreading misinformation, as it generates a lot of clicks and advertising revenue with controversial views. Therefore, it is important to educate oneself and keep an open mind not to counteract the progress the world is already making against the pandemic.

Today we will take a look at 3 myths that often circulate around PCR.

The Public Health Agency has said that PCR does not detect COVID


The Swedish Public Health Agency wrote an article a while ago that could easily be misinterpreted and has added fuel to the fire of myths that PCR tests do not work.

The sentence in question is, “The PCR technology used in tests to detect viruses cannot distinguish between viruses capable of infecting cells and viruses that have been rendered harmless by the immune system, and therefore these tests cannot be used to determine whether someone is infectious or not.”

Just as the sentence reads, PCR tests cannot determine if you are infectious. However, PCR can definitely determine if you are carrying the disease. An important distinction in order to understand the real meaning of the article.

There was also a popular clip circulated featuring Kary Mullis, the inventor of the PCR test and Nobel Prize winner. The clip was taken completely out of context to spread misinformation and is about much the same thing FHM went public with.

The article in question was old and was about PCR tests to detect HIV infection, where “Kary Mullis” described it like this:

“PCR is intended to identify substances qualitatively, but by its very nature, is unsuited for estimating numbers. Although there is a common misimpression that the viral load tests actually count the number of viruses in the blood, these tests cannot detect free, infectious viruses at all; they can only detect proteins that are believed, in some cases wrongly, to be unique to HIV. The tests can detect genetic sequences of viruses, but not viruses themselves.”

There are 3 errors in this myth.

  1. It was not a quote from Kary Mullis, rather an article written by John Lauritsen.
  2. It is not about COVID but about HIV.
  3. The meaning is exactly the same. It refers to the fact that PCR tests cannot determine how infectious the person with HIV is. That is, how easily the person in question can spread the virus.

PCR tests often provide incorrect test results.


Both at the beginning of the pandemic and over time, numbers and percentages have been thrown around with the number of false responses that PCR yields. Aside from the fact that these numbers are often manipulated and biased, two categories determine the reliability of a PCR test.

  1. When the test was taken

A determining factor in how reliable a PCR test is depends on when it was taken. When symptoms are at their worst at the beginning of the infection, the virus’ genome ends up in the throat and nose. As time goes by, the genome disappears, making it more difficult to get a reliable result. This is why quarantine and restrictions are referred to those who have been infected, as PCR tests can give a negative result after, say, 8 days while you are still carrying the disease. If you get tested as soon as possible when you show symptoms, you will get a definite result.

  1. How the test was performed

When PCR tests first started to be used for COVID testing, it gave much less reliable test results than it now does. This is simply because the demand for PCR testing increased enormously, leading to staff shortages and stress that affected the reliability of test results. Now that the situation has stabilised and healthcare has caught up, this is no longer a problem.

It is also important to remember that no test in the world can give 100% accurate test results. Although the chance of a false result is extremely low, in rare cases, it can occur.

PCR testing is painful


PCR tests are relatively easy and painless to perform. In some cases, having a test swab in your throat can cause discomfort, and you may feel the need to cough, which is perfectly normal. When taken through the nostril, it may tickle and induce sneezing, which is also perfectly normal. On the whole, the PCR test is not painful at all.

Do you have any other questions or concerns about PCR testing? Contact us, and we will answer them right away.