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#koronawirus
#chiny

I to by było na tyle propagandy, że chińskie testy na koronawirusa są niskiej jakości.

https://www.scmp.com/news/china/science/article/3085263/chinese-covid-19-test-kit-outstrips-foreign-alternatives-dutch
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CHINESE COVID-19 TEST KIT OUTPERFORMED EQUIVALENT PRODUCTS FROM KOREA, GERMANY IN DUTCH RESEARCH

Product made by Shenzen-based biotech company BGI Group gets top marks in sensitivity test for gene that affects how the novel coronavirus replicates

Increased sensitivity helps to detect infection in people with only mild or no symptoms, head of research team says


A Chinese Covid-19 test kit outperformed equivalent products made in South Korea, Germany, Spain and Britain, according to a study by scientists in the Netherlands.

In laboratory tests, the commercially available reverse transcriptase-polymerase chain reaction (RT-PCR) kit made by Shenzen-based biotech company BGI Group achieved the lowest limit of detection (LOD) score, suggesting it was more sensitive to the presence of the coronavirus than comparable products.

In scientific testing, an LOD is the lowest quantity of a substance that can be distinguished from a total absence of that substance with almost 100 per cent accuracy. In this case, the researchers were looking at test kits that identify the ORF1ab gene, which affects how the coronavirus replicates and how virulent it is.

The research was carried out by a team from the National Institute for Public Health and the Environment, an independent agency under the Dutch health ministry, led by virologist Dr Adam Meijer.

The results were published last month on bioRxiv, a preprint website for scientific studies that have not been peer-reviewed.

In the test, the Chinese kit returned an LOD of 4.3 copies (of the gene) per millilitre, followed by the South Korean product with 4.8. The German and Spanish kits both scored 18, while the British kit fared worst of all with 23.


When asked about the significance of the results, Meijer told the South China Morning Post that all of the products were of a suitable quality for mass testing for Covid-19, but the ones with a greater degree of sensitivity would be preferable in certain situations.

“When you expect low viral loads because of the nature of the patients being tested – such as health care workers with mild or no symptoms, or patients during later stages of the infection – it is best to choose a test that has the highest sensitivity,” he said.

However, while products’ sensitivity could be measured in a laboratory, the actual performance of a test kit was affected by many other factors, such as the quality of swab samples, Meijer said.

For instance, while some Chinese nasal and oral swab tests had returned accuracy levels as low as 30 per cent in earlier studies, that was likely a result of the samples not being taken properly. In more typical tests, with larger numbers of patients, the accuracy rate rose to 96 per cent, he said.

Even the in-house test kit developed by the Dutch institute – which had a sensitivity higher than any of the commercial products – was not 100 per cent accurate and returned false negatives for some samples with very low or damaged viral loads. Ensuring samples were properly taken and stored was more important, Meijer said.

Although China is a major supplier of personal protective equipment and testing kits, it has faced criticism in some countries over the quality of its products.

In April, the Indian government cancelled an order for Chinese test kits after accusing them of being defective, while a Czech hygienist said in March that up to 80 per cent of Chinese rapid coronavirus test kits she had looked at were faulty.


Beijing dismissed both allegations, saying some countries, like India, were not storing or transporting the kits properly, which affected their efficacy.

Meijer said his study did not include any test kits made in the United States as they either did not meet European quality standards or were not available at the time.
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