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.

Formulation

[Preservation]

Storage: 5-25℃ Expiration date: 12 months Please refer to the outer box for the production date and expiration date.

[Sample Requirements] The collected nasopharyngeal swab samples should be transported at 2°C-8°C and submitted for inspection immediately. Sample transport and storage time should be no later than 48h.

[Testing method]

1. Before sampling, mark the relevant sample information on the label of the sampling tube.

2. Use a sampling swab to sample at the nasopharynx up to different sampling requirements.

3. Sampling methods are below:

a. Nasal swab: Gently insert the swab head into the nasal condyle of the nasal passage, stay for a while and then slowly turn it out. Wipe the other nostril with another swab, immerse the swab head in the sampling solution, and discard the tail.

b. Pharyngeal swab: Wipe the bilateral pharyngeal tonsils and posterior pharyngeal wall with the swab, immerse the swab head in the sampling solution, and discard the tail.

4. Quickly place the swab into the sampling tube.

5. Break the sampling swab above the sampling tube, and tighten the tube cap.

6. Freshly collected clinical specimens should be delivered to the laboratory within 2 hours at 2°C-8°C.

[Interpretation of results]

If the collected sampling solution turns yellow or turbid, the sample should be re-sampled for testing.

[Method limitations]

1. Contaminated samples after collection will affect the final results.

2. Store samples at inappropriate temperature will affect the final results.

[Product Index]

2.1 Sampling solution

2.1.1 Appearance

Clear pink liquid.

2.1.2 Quantity

Not less than the indicated amount (3.5mL).

2.1.3 pH

7.0-7.6 at 20°C-25°C

2.1.4 Freezing point osmotic pressure

330±30 mOsm/kg

2.1.5 Sterile

Negative

2.2 Sampling swab

Length: 15cm±0.8cm

2.3 glass bead

Diameter: 3.0±0.8mm

2.4 Sample preservation effect

The virus samples are stored in the virus sampling kit at 2℃-8℃ for 48h, and the RT-PCR nucleic acid test is positive.

2.5 Difference between batches

Three consecutive batches of products should meet the requirements of 2.1, 2.2, 2.3

[Notes]

1. This product is for in vitro diagnostic use only.

2. This product is intended for use by trained laboratory personnel only.

3. Gloves and masks should be worn for protection while using the product.

4. Discarded specimen collection liquid should be treated by moist heat sterilization.

5. Prohibited use when solution is out of date, the sampling solution turns yellow, leakage.

6.The BSA in the export VTM is replaced by a kind of amino acid that isolated from E coli. fermentation product to meet the requirements of the local laws and regulations.

Production license number: 20180033

[Medical device registration number / product technical requirement number] 20182400236

[Specification approval date and modification date] September 01, 2020