The difference between antibody detection and nucleic acid detection
According to the report of the British "Nature" website on the 26th, British government officials said that the United Kingdom may carry out large-scale coronavirus antibody testing in the next few days to determine who has been infected with the new coronavirus and has antibodies. If everything goes according to plan, the UK may become the first country to carry out such tests on a large scale at home. Antibody testing is to detect the level of antibodies in human blood. The average time is 15 to 60 minutes. It can be tested by the people at home. It can be widely used in a short period of time. Therefore, there is a detection window period and therefore cannot replace nucleic acid detection. However, the researchers warn that it will be a huge challenge to correctly verify the accuracy of such tests and to manufacture test kits on a large scale.
On the 25th, British government officials said that the UK has ordered 3.5 million antibody test kits and plans to order millions more. The test method will analyze blood drops to determine who has been infected with the new coronavirus and has antibodies-regardless of whether they have symptoms of new coronary pneumonia, which will help researchers better understand how the new virus spreads.
Sharon Peacock, director of the National Infection Service of the British Department of Public Health (PHE), said that people should be able to receive these "serological tests" in a few days instead of weeks or months. Peacock pointed out that such tests can be performed at home, but these test reagents have not yet arrived.
Peacock said that PHE is evaluating new tests to ensure that they meet the requirements, and the evaluation will end this weekend. But David Wyles, an immunologist at the University of Birmingham in the UK, said that the supply of test kits may still be limited. During the global pandemic, it is a huge challenge for the company to manufacture millions of tests to ensure government supply. It is not clear which company is responsible for developing such tests. A PHE spokesman said that the government is negotiating with a number of companies.
A few days ago, Feng Luzhao, a researcher at the Chinese Center for Disease Control and Prevention, said at a press conference that new coronary pneumonia detection reagents mainly include two types, one is nucleic acid detection reagents, and the other is antibody detection reagents. Nucleic acid detection is the direct detection of viral nucleic acid in collected samples, with strong specificity and relatively high sensitivity, and is currently the main detection method. Antibody testing is to detect the level of antibodies in the human blood. In the early stages of disease infection, the body may not have produced antibodies, so it has a window of detection.
Compared with nucleic acid detection, the advantage of antibody detection is that it is not limited by the detection conditions, can be widely promoted in a short time, and can be screened for a wide range, which is essential for evaluating and mastering the epidemic situation and taking follow-up measures.
Previously, France mainly adopted nucleic acid testing, but due to the lack of medical materials such as masks and protective clothing, a large number of laboratories were unable to invest in testing, which greatly weakened the national testing capacity. The antibody test is easy to operate and can be tested by the people at home, which can be widely promoted in a short time.
Professor Drosten from Germany introduced that so far, German medical and health institutions usually use fluorescent quantitative polymerase chain reaction (PCR) to detect the specific sequence of the new coronavirus, and thus to confirm whether the patient is infected with the new coronavirus. Due to the complicated operation of this nucleic acid detection process, strict requirements are imposed on sampling and testing personnel, laboratories and kits. During the operation process, it is also necessary to prevent the risk of aerosol contamination on the detection personnel, so it is difficult to increase it in a large scale in a short period Test ability.
With more than 400,000 people diagnosed worldwide, Drosten believes that in addition to PCR testing, antibody testing is also very important. After infection with the new coronavirus, patients need about 10 days to develop antibodies, and then more and more. Knowing exactly how many neutralizing antibodies the immune system has is very important for vaccine development and testing.