Just yesterday, the National Health Commission issued an announcement, which was madly reposted in the circle of friends because of the sentence "nucleic acid must be extracted for dilution and mixed sample detection, and the "one-step method" is prohibited.
From a technical point of view, there is nothing wrong with this sentence. The one-step method mostly uses direct lysis, and then amplifies after centrifugation or without centrifugation. The reason why this method cannot be used for mixed sample detection is also mixed sample The reason why the test was dissed by many examiners at the beginning, mixing multiple specimens means that the sample is diluted, and dilution also means that there is a risk of missed testing. To
However, as many places in the country began to carry out large-scale nucleic acid screening, a large number of samples followed, and then mixed sample testing was once again put on the discussion table. In disease control, blood stations, etc., blood samples were mixed. In fact, it is a relatively common method, but the blood sample is a homogeneous sample after all, and the new crown is a non-homogeneous swab sample, which is also the culprit of the current epidemic. Can a mixed sample of the new crown work?
I don’t know if you have read this document of the Health Commission carefully. In this document, the recommended number of mixed samples is 5, each 200μl, which adds up to exactly 1mL. I think this is why it is recommended to mix 5 with 1 The reason is that the mixed liquid volume is too large or the single volume is too small. Don't say that it can be enriched by centrifugation, this is a virus, and no one can be centrifuged at a speed of tens of thousands of speeds.
This version of the technical guidelines for mixed sample testing basically takes into account all the issues that can be considered. It is currently the most complete technical solution for mixed sample testing. Regarding the reason why the "one-step method" cannot be used, I think it is probably because the one-step method is common. The sample volume is relatively small and direct lysis is used. The purity of the nucleic acid is not high, and the presence of protein and polysaccharides will affect the results.
The purpose of mixed sample detection is to improve the detection efficiency and reduce the detection cost. If the cost factor can be put later, there is also a mixed sample detection scheme that is also good, that is, nucleic acid extraction through a single sample and magnetic bead transfer mixing method Concentrate. This solution uses multiple extraction reagents + 1 detection reagent combination, which can reduce the cost of detection reagents, but the cost of extraction reagents does not decrease much.
The inactivated Virus Transport Media developed by Desheng provides a strong guarantee for nucleic acid detection. The company has also specially tested whether the samples stored in the company’s Virus Transport Media are more suitable for one-step detection or magnetic bead detection. In short, two kinds of detection Each method has its own advantages. If you need more professional and detailed knowledge about the product, you can call our customer service or direct online consultation on the official website, and Desun will have professional technology to answer you.
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