Link : https://elpais.com/sociedad/2020-03-25/los-test-rapidos-de-coronavirus-comprados-en-china-no-funcionan.html

Google translation

Rapid tests for coronaviruses purchased in China do not work well. Microbiology laboratories report that the tests acquired by the Government have a sensitivity of 30% when they should exceed 80%.


Madrid - MAR 26, 2020 - 12:19 CET


The much-announced rapid tests for coronavirus with which the Government wanted to start testing the broader layers of the population to find out what the real size of the contagion is in Spain do not work well. This has been confirmed by several microbiology laboratories of large hospitals in the analyzes that have been made of the kits recently arrived from China. The results of these preliminary tests are discouraging: "They do not detect the positive cases as expected", says a source who has participated in the tests and who asks for anonymity.

The rapid tests, manufactured by the Chinese company Bioeasy, based in Shenzhen, one of the technological poles of the Asian country , have a sensitivity of 30%, when it should be higher than 80%, these sources indicate.

One of the microbiologists who has analyzed the Chinese test assures: "With that value it does not make sense to use these tests." The conclusion of the experts who have evaluated these detection kits is that they will have to continue using the current test, the PCR. This has been reported to the Carlos III Health Institute, under the Ministry of Health.


The coronavirus detection tests currently used by the microbiology laboratories of Spanish hospitals are based on a molecular technique called PCR (polymerase chain reaction) that detects the RNA of the virus in an exudate sample nasopharyngeal (a stick is inserted through the nose or through the mouth to collect it). It is a laborious technique, which requires specific equipment (the reactions take place in machines called thermocyclists in real time) and up to four hours until the result is obtained. The badly called rapid tests of Galicia, Andalusia or the one that began this Wednesday the Madrid City Council, in which a sample is taken from the patient without the patient leaving the car, are quick only because of the way the sample is taken, because the analysis is still PCR in the laboratory.

Rapid tests, on the other hand, work in a similar way to pregnancy tests: the sample also taken from the nasopharyngeal area is diluted and deposited in a cartridge with a test strip that marks with lines if it is positive, negative or invalid. The tests detect the presence of antigen and the result is obtained in 10 or 15 minutes. The Government, which has bought 340,000 tests, intends to subject the health workers and the elderly admitted to the residences to a massive screening and then extend it to another population. This Wednesday he announced that he has ordered 5.5 million of this type of test , but it is unknown if they are from the same manufacturer.

These tests purchased in China had to serve as screening, that is, when they detect a positive, it can already be diagnosed and treated accordingly (isolating it, preventing its contacts, etc.). If the Chinese test were of sufficient quality, added the sources consulted, only the negative or doubtful results would require a subsequent PCR to confirm.



But with the low sensitivity of the material purchased from Bioeasy, it does not make sense to use them to do this massive screening because they would not take away PCR work, that is, in many cases patients would have to be taken again and taken to the laboratory. Due to its low sensitivity, when the test is negative, it is not possible to know if it is a true negative or a false negative. That is, the patient may actually be infected.

With the preliminary tests carried out by these microbiology laboratories, the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) has prepared a positioning document, to which EL PAÍS had access, which it has already sent to the health authorities, including the Institute of Health Carlos III. His recommendation is not to use these tests and to continue doing PCR.

To questions from EL PAÍS, the Ministry of Health confirmed late Wednesday the poor results of the sensitivity and specificity analyzes. The Carlos III Health Institute, said a spokesman, "has detected a sensitivity that does not correspond to what is established in the technical sheet." According to Health, it is a determined item and located in the Community of Madrid and has given an order for it to be withdrawn. He added that he has ordered the manufacturer to replace it and that all the tests purchased by the Government are approved for use in Europe. The Carlos III Health Institute posted a video explaining how the test works on their Twitter account on Tuesday afternoon. It shows what the box contains with which 25 determinations can be made.

"The studies," says the document of the scientific society that groups microbiologists in Spain, "indicate a sensitivity of less than 30% and a specificity of 100% in populations that go to hospital emergencies in which the percentage of positivity of the PCR is 84% ​​and of health workers in whom the percentage of positivity is 50%. "The work concludes:" These results would prevent its routine introduction ”. SEIMC experts assure that there are other techniques, "formats that require fluorescent reading", that are "pending evaluation".

After its analysis, this scientific society considers that "antigen detection [the recently arrived rapid tests] could have an application in those cases where a rapid diagnosis is desired, especially because it has a high positive predictive value". But he adds that "later, PCR should be done if antigen detection is negative and there is a high suspicion of Covid-19." His conclusion is clear: "Today, PCR continues to be the test of choice for processing a large number of samples."

Given the "spectacular increase" in cases, the SEIMC document ensures that a "rapid diagnosis of such cases at the hospital level is relevant to quickly identify, isolate and treat" patients and to facilitate "decongestion of emergencies". "For this we need rapid tests with high sensitivity," he adds. They are very necessary, the document also points out, to "promote the incorporation of health professionals who have been with Covid-19".

China and cheap products....

China has scammed them again

Nawaoo the Chinese are playing with innocent people's lives

https://www.irozhlas.cz/zpravy-domov/ostrava-rychlotesty-koronavirus_2003231414_sot

Link from Czech Republic newspaper ( use Google translate )


The Czech Republic received 150,000 coronavirus test kits as gift from China.

About 80% of the test kits give false results.

Czechs have gone back to more reliable traditional tests, of which they perform 900 per day with very low error