Description
Viral Transport Medium(VTM)
[Product Name]
Viral Transport Medium
[Specifications]
20 servings / box
[Product Use]
Collection, storage and transportation of human nasopharyngeal virus samples
[Description]
The virus sampling kit is based on Hank’s solution. The solution contains inorganic salts, amino acids, and protein-stable ingredients. The virus sampling kit has a stable osmotic pressure, which provides a stable transport and storage environment for nasopharyngeal swab samples. Samples are sent to the laboratory for follow-up testing to determine whether the collected samples are infected with the virus.
[Main Ingredients]
Per serving:
|
MT0301 |
MT0301 |
Main Ingredients |
Sample tube |
1 sampling tube with 3.5ml sampling solution |
1 sampling tube with 3.5ml sampling solution |
Sampling tube: 100mmx16mm 120mmx16mm
Sampling solution:
sodium chloride: 0.8%,
potassium chloride: 0.04%,
calcium chloride: 0.014%,
Magnesium sulfate heptahydrate: 0.02%,
Disodium hydrogen phosphate heptahydrate: 0.012%,
potassium dihydrogen phosphate: 0.006%,
sodium bicarbonate: 0.035%,
glucose: 0.1%,
phenol red sodium salt: 0.002%. |
Sampling swab |
1 sampling swabs |
2 sampling swabs |
|
[Product performance]
1. In 2006, virus preservation solution was Hank’s solution.
In 2010, upgrade to VTM, with a higher PCR test positive rate and shorter test time.VTM is recommended by the World Health Organization and the National Influenza Center of China.
Based on Hank ’s, VTM adds HEPES, amino acids, glycerin and other ingredients, with higher PCR positive rate.
Experiment Design |
1.A type H3N2 virus (virus titer is greater than 1e6), diluted 10 times, 100 times, 1000 times and 10,000 times
with VTM and Hank ’s.
2. Refer to the temperature of the samples (cold or room temperature) and the time of inspection (within 24 hours)
after sampling, the VTM and Hank’s of different dilutions are stored at 4 ° C and 25 ° C for 24 hours.
3. CT values are detected with real-time PCR instrument |

2.In real work, almost every laboratory will have a positive PCR test, but the virus cannot be isolated.
The reason is that virus isolation is performed after the positive PCR result, time difference is the main reason for this problem.
Experiment Design |
1. The A-type H1N1 virus and H3N2 virus suspensions (the virus titer is 1×106, which is equivalent to the virus level while the actual sampling conditions are not good) are stored in VTM solution.
2. After storage at 2-8 ° C and room temperature for 24h and 48h, VTM solution with virus was inoculated in MDCK cells and incubated to produce CPE (lesion response), and then incubated with fluorescein-labeled antibodies.
3. The number of virus particles infected with MDCK cells was detected. That is, the number of green fluorescent
stove points in the figure below. |
Experiment
Results |
Regardless of the virus is stored in VTM at 2-8 ° C or room temperature, the virus can be isolated within 48 hours. |

3.The virus sample collected in the swab can only be detected by PCR and separated from the virus if it is successfully released into the sampling solution.
The release rate of the swab greatly affected the positive rate of PCR detection and virus isolation.
In order to increase the swab release rate, we innovatively add specially treated glass elution beads to the sampling solution.
Experiments have shown that the sample release rate has increased 3 times.
The used sample collection tube should be placed on an oscillator.
The vortex generated is shaken to drive the elution beads to hit the sampling swab, so that the cells and virus particles adhered to the swab are released into the virus sampling solution.
Experiment Design |
The number of virus particles eluted into the sampling solution can be accurately calculated by using immunofluorescence method and observing live fluorescent particles labeled with green fluorescent protein (GFP) under the fluorescent inverted
microscope. |
Experiment Results |
The sample release rate has increased 3 times. |
4.Mold contaminationafter sample collection is a problem for the laboratory to prepare sampling liquid or other brands of sampling tubes.
In order to inhibit bacteria in the early sampling solution, penicillin (inhibiting bacteria) and amphotericin B (inhibiting mold) are added.
Relatively, penicillin is still stable at normal temperature, while amphotericin B is stable only at -20 ° C. The activity of amphotericin B decreases rapidly at room temperature until it disappears.
That is the main reason why most of the sampling tubes cannot be stored at room temperature.

Not only solves the problem of allergies to penicillin in some people, but also raises normal temperature Antibacterial effect of the stored sampling solution on bacteria.
The amphotericin Bwas replaced with a normal-temperature stable fungal antibiotic, which solved the problem of mold contamination after sampling and saved the sample solution at room temperature.