As the name implies, virus preservation solution is a protective liquid medium added to virus sampling tubes to protect virus specimens.
Usually, when nucleic acid testing is performed, the sample collection site is not able to directly perform nucleic acid PCR, and the samples collected from the swab need to be transferred for testing, which requires the use of virus preservation fluid.
There are two types of virus preservation solutions.
Non-inactivated virus preservation solution is mainly based on the transport medium as a modified virus maintenance fluid type preservation solution, which can protect the virus protein shell and viral nucleic acid DNA or RNA, so that the virus in vitro with protein antigen epitopes and nucleic acid integrity, there will be a certain risk of infection when the operation is not done properly. Prolonged storage after sampling requires maintaining strict low temperature.
Inactivated virus preservation solution is mainly a modified nucleic acid extraction lysis solution, which contains a high concentration of lysis salts that can rapidly and efficiently inactivate the viral proteins in the sample to be tested, effectively preventing infection, and contains Rnase inhibitors that protect the viral nucleic acids from degradation, so that subsequent NT-PCR experiments can make a diagnosis as long as the viral nucleic acids can be detected. The subsequent NT-PCR test can make a diagnosis as long as the nucleic acid of the virus is detected. It can be stored at room temperature for a relatively long time.
Virus detection differs from conventional biochemical assays in that the virus itself is a simple microorganism that must live in a living cell. After sampling, the virus leaves the host cell and its protein shell and nucleic acid are quickly degraded in the sampling tube, so that the nucleic acid test is unable to determine whether the initial sample contains the virus, which can easily result in false negatives.
The specific preservation time of virus preservation solution should be distinguished between different types of preservation solutions. Usually, before sampling, virus preservation solution, whether inactivated or non-inactivated, can be stored at room temperature for six months or even a year, but the preservation time after sampling is very short. This is because the preservation time does not depend on the quality of the preservation solution, but on the characteristics of the virus or nucleic acid itself.
Bioviruses are tiny organisms, much smaller than fungi or bacteria, that must parasitize and proliferate by replication in living cells, and are non-cellular organisms. Therefore, whether inactivated or non-inactivated, the virus can only survive for a short time after sampling. Without virus preservation solution, the virus will degrade substantially in vitro within a few minutes. The sampling tube is mainly used for virus nucleic acid detection, so although the inactivated preservation solution makes the virus lysis, but the RNA enzyme inhibitor added inside can protect its nucleic acid, the experiment can be diagnosed as long as the nucleic acid can be detected.
Another important factor that affects the preservation time of viruses is the temperature. Generally, inactivated solutions are stored at 4 degrees Celsius for one week, -20 degrees Celsius for one month, and -80 degrees Celsius for one year because they only need to protect the nucleic acid from degradation. If the non-inactivated preservation solution cannot be tested in time after sampling, it must be stored at 4 degrees Celsius for no more than 48 hours, and if it cannot be sent to the testing site in time, it needs to be stored at -70 degrees Celsius or below.
