At present, the form of prevention and control of the new coronavirus is still very severe. As the first step of nucleic acid testing, the importance of sample collection and preservation is undoubted. The inspection industry often says "garbage in, garbage out". The first important factor is sample collection. If there is a problem with the sample collection, no matter how well the subsequent work is done, the result will be invalid. Choosing the correct virus preservation solution and collection tube can make the new crown detection more effective!
Almost all virus preservation liquids on the market directly preserve live viruses, causing medical staff in sampling, transportation, and testing to face a higher risk of infection. In response to this situation, the front line of anti-epidemics needs samples that can directly inactivate viruses. Preservation solution, but it should be noted that while inactivating the virus, consideration should also be given to whether the preservation solution can stably preserve the integrity of the viral nucleic acid, so as to avoid degradation of the nucleic acid in the sample before the test, resulting in a "false negative" nucleic acid test. Desheng does not contain guanidine salt virus preservation solution to minimize the risk of "false negative".
We compared the effects of preservation solutions containing guanidine hydrochloride and guanidine isothiocyanate on the market with Kangwei Century Preservation Solution without guanidine salt in the preservation of poultry coronavirus at 37°C. It turns out that the main ingredient is the preservation solution of guanidine salt, and the preservation effect is very unsatisfactory!
The same conditions are 37°C. After storage for 1-7 days, the preservation efficiency of viral nucleic acid is basically constant at 100% using Kangwei Century Preservation Solution; while the other two guanidine salt component preservation solutions are used, the preservation efficiency of viral nucleic acid gradually decreases. By the 7th day, it was already below 20%, indicating that the RNA was degrading violently over time!
Guanidine salt (guanidine isothiocyanate or guanidine hydrochloride, etc.), as a classic protein denaturant, is often used for cell lysis in nucleic acid extraction and can also achieve the effect of inactivating viruses. However, the guanidine salt component does not have the ability to perform under normal temperature conditions. The ability to preserve viral nucleic acid is very easy to cause sample degradation, so it is not suitable for the preservation of new coronavirus samples, so it is strongly recommended that you choose a virus preservation solution that does not contain guanidine salts.
Here, we appeal to the majority of medical workers, if your sampling purpose is for nucleic acid testing and you do not need to cultivate live viruses, then you need to pay attention to the following aspects when choosing a virus preservation solution:
1. Use a preservation solution that can inactivate the virus
The current nucleic acid detection is to detect the viral RNA in the sample, and the virus needs to be lysed, so as long as it can ensure the integrity and stability of the viral nucleic acid, it does not need to save the live virus. Therefore, in the current situation of fighting against the new coronavirus epidemic, it is more ideal to inactivate the virus while collecting samples. Some manufacturers on the market have also introduced inactivated storage solutions, but the inactivated ingredients used are guanidine salts. The results of comparative experiments show that the guanidine salt component storage solutions do not have the ability to preserve viral nucleic acids under normal temperature conditions, which can easily cause sample degradation It is not suitable for the preservation of new coronavirus samples. Therefore, we recommend a virus preservation solution containing non-guanidine salt protein denaturants, which can inactivate the virus and ensure that the viral nucleic acid is not degraded when stored at room temperature.
2. The volume of the preservation solution in the sampling tube should be appropriate
It is very important to choose a storage solution with an appropriate volume: (1) If each sample is sampled separately, it is recommended that you choose a virus sampling tube with 1ml storage solution. Not only the sampling volume can meet the needs of downstream nucleic acid extraction and detection, but also compared with 3ml storage solution. The virus concentration has increased by 3 times! ②If a large-scale initial screening and mixed test is performed, the swab samples of 3-5 people are placed in the same sampling tube. It is recommended that you use a virus sampling tube with 3ml preservation solution to make the sample volume meet the needs of downstream nucleic acid extraction and improve detection. Efficiency, reduce testing costs.
3. Use a virus preservation solution that can transport and preserve samples at room temperature
Because RNA is unstable, traditional virus sampling tubes need to be transported to the laboratory within 48 hours at 4°C. If the transportation temperature is not up to standard, it may cause virus nucleic acid degradation, resulting in "false negative" test results! In contrast, if Kangwei Century's virus preservation solution that can transport and stably store viral nucleic acids at room temperature is used, the problem of sample transportation can be solved, thereby improving the accuracy of the test results.
4. Use a virus preservation solution that can protect samples from high temperature inactivation
The relevant guidelines of the National Health Commission require high temperature inactivation of samples before extracting viral nucleic acid (treatment above 56°C for 30 minutes), but the Beijing Center for Disease Control and Prevention, Beijing Preventive Medicine Research Center and other institutions published research papers in Clinical Chemistry It shows that high temperature inactivation will cause the degradation of viral nucleic acid, thereby reducing the detection rate of viral nucleic acid, which is one of the reasons for the high false negative rate of new coronavirus nucleic acid detection. Experiments have verified that when the Desheng virus sample preservation solution is used to store the samples, high temperature inactivation has no significant effect on the integrity of the coronavirus nucleic acid.
The virus preservation solutions developed and produced by Desheng are divided into inactivated and non-inactivated types. Different preservation solutions can be selected according to different experimental requirements and detection conditions. If you have any questions or needs, please call for detailed inquiry. Choosing Desheng virus preservation solution is your right choice.
