How to choose sample preservation solution？

1、How to choose the type of preservation solution？

According to the composition of the liquid, it can be roughly divided into two types, inactivated and non-inactivated. Among them, the inactivated virus preservation solution contains Tris, guanidine salt, EDTA, etc., whose main purpose is to destroy the protein coats of cells and viruses, and release nucleic acids, so that nucleic acid detection can be performed by subsequent real-time fluorescent RT-PCR to determine whether the sample contains the virus sequence. The inactivated preservation solution can effectively lyse the structure of the virus and make it lose the ability to infect. It is safer for the inspectors and can effectively inhibit the reproduction of fungi and bacteria. However, due to the addition of guanidine salt, it may leave salt ions in the nucleic acid solution. If the concentration is too high, and if the polymerase activity in the downstream test kit is highly sensitive to the salt ion concentration, it will cause the Ct value of the test to lag or even false negative.

The non-inactivated preservation solution generally includes UTM and VTM types. The components of the non-inactivated virus preservation solution are mainly based on Hank's solution. On the basis of Hank's solution, it also adds various buffers such as gentamicin, fungal antibiotics, BSA (bovine The fifth component of serum albumin), biological buffer HEPES, amino acids, cryoprotectants, glycerin and other components are used to

maintain the integrity and biological activity of the virus. The non-inactivated preservation solution preserves the integrity of the virus better, so the detection rate is higher, but it needs water bath inactivation treatment before detection.

Users can choose the type of preservation solution reasonably according to their own usage scenarios.

2、After sample storage, what is the detection sensitivity?

In order to facilitate the selection of different types of storage tubes, we tested different brands, under 4℃ storage conditions, and different storage days (the first day, the third day, the seventh day, the fourteenth day, and the

thirtieth day). The sensitivity of nucleic acid detection of the new coronavirus

is as follows.

After 14 days of storage at 4°C, the comparison of the preservation effec t of different brands of UTM

In order to facilitate the selection of different types of preservation tubes, we tested the sensitivity of nucleic acid detection of the new coronavirus under different brands, room temperature storage conditions, and different storage days (the first day, the third day, and the seventh day). The results are as follows.

After 7 days of storage at room temperature, comparison of storage effects of different brands of ITM

After 7 days of storage at room temperature, comparison of storage effects of different brands of VTM

After 7 days of storage at room temperature, comparison of storage effects of different brands of UTM

In general, the Ct value of Bioteke is lower than that of some common brands on the market, regardless of room temperature or 4℃ storage conditions. The detection sensitivity is higher and the test results are more stable.

3、 What is the effect of inactivation preservation solution (ITM)?

Table. Number of plaque at different times of inactivation (0, 1, 2, 5, 10, 20, 40min)

Figures of plaque at different times of inactivation (0, 1 5 ,40 min) (plaque is shown in the red box)

Conclusions:

Bioteke product, inactivating transport media （ ITM ） , can effectively inactivate the HSV 1 virus.

4、Features of Bioteke Virus Preservation Solution

a) Provide multiple types of preservation solutions such as UTM, VTM and ITM;

b) It can be used with Bioteke swab to meet multiple needs;

c) Selected raw materials, matched with Bioteke nucleic acid extraction kit to ensure the initial copy quantity of the sample.

5.%2 The inspection reports that Bioteke has obtained for Virus Preservation Solution

Attachment: production environment

References

【1】《New Coronary Pneumonia Laboratory Testing Technology Guide (Third Edition)》, Chinese Center for Disease Control and Prevention.

【2】《Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Patients Under Investigation (PUIs) for 2019 Novel Coronavirus (2019-nCoV)》.

【 3 】 A Stephen K Hashmi, Miriam Bührle, Michael Wöl fle,et al.

Qualification of

high-recovery, flocked swabs as compared to traditional rayon swabs for microbiological environmental monitoring of surfaces[J]. pda journal of pharmaceutical science & technology, 2008, 62(3):191.

【4】 Daley P, Castriciano S, Chernesky M, Smieja M. Comparison of flocked and rayon swabs for collection of respiratory epithelial cells from uninfected volunteers and symptomatic patients. J Clin Microbiol.

2006;44(6):2265-2267. doi:10.1128/JCM.02055-05.

【5】Ba Huajie, Jin Ming, Wang Linsheng, et al. Comparison of DNA typing effects between nylon flocking swabs and cotton swabs[J]. Chinese Journal of Forensic Medicine, 2015(03):53-56.

【6】Liu Yanbin, Liu Tao, Cui Yue, Wang Bo, Luo Fengming. Comparison of two sampling methods of nasal swab and throat swab in nucleic acid screening for new coronavirus pneumonia[J]. Chinese Journal of Respiratory and Critical Care, 2020, 02:141-143.