Virus kit production technology has been quite mature, just mass production is difficult, the new crown virus has made the demand for test kits in various countries increased dramatically, and the detection of the new crown virus at least need to be P3 level laboratories, and so led to a lot of countries can't keep up with the testing capacity.
From March, the outbreak of new coronavirus in countries other than China, many countries are generally faced with the problem of insufficient detection capacity, not enough test kits, so what is the principle of the kits to detect the virus? What is the high-tech inside?
The principle of detection
In addition to the prions of the class of organisms, the rest of the virus is composed of protein shells wrapped in nucleic acid, the detection of the class of viruses there are three main approaches:
Nucleic acid detection: the detection of the virus genetic material of the special paragraph (professional name target gene), it proves that there is the existence of the virus.
Antigen detection: the detection of surface proteins or internal nuclear proteins of the pathogen also proves the presence of the virus.
Antibody detection: The immune system produces specific antibodies to antigens that invade the body, and detection of the corresponding antibodies also proves infection with the virus.
While it takes several days for antibodies to be produced in the body, and people with low immunity may have very low antibody counts, resulting in false negatives, antibody testing is generally applicable to recovery testing.
The new coronavirus is a single-stranded RNA virus, and nucleic acid testing is very suitable. The general steps of the test are:
Step 1: Wipe a swab in the patient's pharynx to get the pathogen
Step 2: Put the virus into a nutrient solution that expands the virus number hundreds of times
Step 3: Pour it into a separate bottle, which has an inhibitor that kills the virus. organisms other than the virus
Step 4: Isolate the virus and add a special test solution to make the virus visible
Depending on the principle of the test, the method and timing of the test may be different. For example, the common fluorescent quantitative PCR, after isolating the RNA of the virus and then reverse transcribing the RNA into DNA, then going through a series of complex reactions to make the resulting product fluoresce, the Each DNA strand amplified generates a fluorescent molecule that can be detected by the instrument.
Production of kits
As long as the nucleic acid sequence of the virus, the production of virus detection kits is not difficult, many pharmaceutical companies can produce, a variety of commonly known viruses detection reagents are sold online, hospitals also have some commonly used viruses detection, chemical composition testing kits.
But for a brand new virus, from research and development to large-scale mass production is not only a test of a company's research and development capabilities, such as the new crown pneumonia outbreak, in January, a pharmaceutical company said on condition of anonymity: the whole company has been implemented in three shifts, but 100,000 people per day is already the limit of production.
Taking into account the presence of false negatives and the need to repeat tests on single individuals, the demand for neocoronavirus kits is very high; when the kits are produced, testers need to come into contact with bodily fluids or blood from suspected patients, which can be very dangerous for neocoronaviruses, and at least in P3-level laboratories.
In general, the entire process of nucleic acid testing takes 2 to 6 hours, or 1 to 2 days from collection to results when sample collection, sample transfer and waiting time are included. Some newer tests may shorten the testing time, but whether they can be mass-produced and how accurate they are are are also questions.
China is the only country in the world with a complete industrial chain, some companies can change the type of products in a short time, such as BYD drawings in three days, seven days to produce automated mask machines, 10 days out of the mask, which is all a reflection of the country's complete industrial chain.
Virus detection kit is the same, to achieve large-scale production in a short period of time is difficult, from the production of bio-enzymes, the production of reagent box packaging, the supply of raw materials and so on is a problem, I believe that the world does not have a few countries can do it, but our country took the lead in the first to do it, for the other industrial chain is not complete country, may be raw materials are a problem.