The Dasky Disposable Sampling Tube (Model name: VSM02) is intended for the stabilization, transportation and inactivation of infectious unprocessed nasopharyngeal specimen samples suspected of containing SARS-CoV-2. These devices can be used for collection transport and storage of specimens from the collection site to the laboratory. The specimens collected and stored in a Dasky Disposable Sampling Tube (Model name: VSM02) are suitable for use with compatible laboratory based molecular diagnostic devices.
Device Story
Device consists of plastic transport tube containing 3 mL stabilization media; supplied alone or with nasopharyngeal (NP) nylon flocked swab and optional biosafety bag. Used at collection site by healthcare professionals to collect NP specimens; media lyses cells, disrupts lipid membranes, and denatures proteins to inactivate SARS-CoV-2 and stabilize RNA for transport to laboratory. Specimens stored at 4°C–23°C. Laboratory personnel use compatible molecular diagnostic devices to process samples. Inactivation benefits patient/staff by reducing infectious risk during handling/transport; stabilization ensures sample integrity for accurate molecular testing.
Clinical Evidence
Bench testing only. LoD verified at 70 GCE/mL. Stability testing confirmed RNA integrity at 23°C for 48 hours and 4°C for 144 hours (Ct deviation < 2). Inactivation efficiency confirmed 100% inactivation of SARS-CoV-2 (10^3 GCE/mL) after 5 minutes exposure via Vero-E6 cell culture assay.
Technological Characteristics
Plastic screw-cap tube containing 3 mL chemical stabilization media. Media components: Tris, Protease K, Guanidine hydrochloride, Dithiothreitol, Triton X-100, distilled water. Single-use; non-sterile. Storage temperature range: 4°C to 23°C.
Indications for Use
Indicated for stabilization, transport, and inactivation of infectious unprocessed nasopharyngeal specimens suspected of containing SARS-CoV-2. For prescription use only.
Regulatory Classification
Identification
A microbial nucleic acid storage and stabilization device is a device that consists of a container and reagents intended to stabilize microbial nucleic acids in human specimens for subsequent isolation and purification of nucleic acids for further molecular testing. The device is not intended for preserving morphology or viability of microorganisms.
Special Controls
The special controls for this device are: (1) The intended use for the 21 CFR 809.10 labeling must include a detailed description of microorganisms and types of human specimens intended to be preserved. (2) The 21 CFR 809.10(b) labeling must include: (i) A detailed device description, including all device components. (ii) Performance characteristics from applicable analytical studies, including but not limited to, nucleic acid stability and microorganism inactivation. (iii) A limiting statement that erroneous results may occur when the transport device is not compatible with molecular testing. (iv) A limiting statement that the device has only been validated to preserve the representative microorganisms used in the analytical studies. (3) Design verification and validation must include the following: (i) Overall device design including all device components and all control elements incorporated into the analytical validation procedures. (ii) Thorough description of the microorganisms and methodology used in the validation of the device including, but not limited to, extraction platforms and assays used for the detection of preserved nucleic acids. (iii) The limit of detection (LoD) of the molecular test used to establish microorganism nucleic acid stability.
*Classification.* Class II (special controls). The special controls for this device are:(1) The intended use for the labeling required under § 809.10 of this chapter must include a detailed description of microorganisms and types of human specimens intended to be preserved.
(2) The labeling required under § 809.10(b) of this chapter must include the following:
(i) A detailed device description, including all device components;
(ii) Performance characteristics from applicable analytical studies, including nucleic acid stability and microorganism inactivation;
(iii) A limiting statement that erroneous results may occur when the transport device is not compatible with molecular testing; and
(iv) A limiting statement that the device has only been validated to preserve the representative microorganisms used in the analytical studies.
(3) Design verification and validation must include the following:
(i) Overall device design, including all device components and all control elements incorporated into the analytical validation procedures;
(ii) Thorough description of the microorganisms and methodology used in the validation of the device including, extraction platforms and assays used for the detection of preserved nucleic acids; and
(iii) The limit of detection (LoD) of the molecular test used to establish microorganism nucleic acid stability.
K233324 — Molecular Transport Media - MTM · Alb Luz · Jun 17, 2024
Submission Summary (Full Text)
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FDA
U.S. FOOD & DRUG
ADMINISTRATION
# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY
## I Background Information:
A 510(k) Number
K211675
B Applicant
Ningbo Dasky Life Science Co., Ltd.
C Proprietary and Established Names
Dasky Disposable Sampling Tube (Model name: VSM02)
D Regulatory Information
| Product Code(s) | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| QBD | Class II | 21 CFR 866.2950 - Microbial Nucleic Acid Storage and Stabilization Device | MI - Microbiology |
## II Submission/Device Overview:
A Purpose for Submission:
To obtain a substantial equivalence determination for the Dasky Disposable Sampling Tube (Model name: VSM02), for the collection, transport and storage of unprocessed samples suspected of containing SARS-CoV-2 virus to the laboratory for downstream testing.
B Measurand:
Storage and stability of nucleic acids from SARS-CoV-2 virus.
C Type of Test:
Microbial nucleic acid storage and stabilization device
Food and Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993-0002
www.fda.gov
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K211675 - Page 2 of 7
## III Intended Use/Indications for Use:
### A Intended Use(s):
See Indications for Use below.
### B Indication(s) for Use:
The Dasky Disposable Sampling Tube (Model name: VSM02) is intended for the stabilization, transportation and inactivation of infectious unprocessed nasopharyngeal specimen samples suspected of containing SARS-CoV-2. These devices can be used for collection transport and storage of specimens from the collection site to the laboratory. The specimens collected and stored in a Dasky Disposable Sampling Tube (Model name: VSM02) are suitable for use with compatible laboratory based molecular diagnostic devices.
### C Special Conditions for Use Statement(s):
For prescription use only.
### D Special Instrument Requirements:
None
## IV Device/System Characteristics:
### A Device Description:
The Dasky Disposable Sampling Tube (Model name: VSM02) consists of a plastic transport tube with media which is supplied alone or in a kit with a nasopharyngeal (NP) swab, and an optional biosafety bag. The plastic transport tube contains 3 mL of the stabilization media. The components of the media are intended to inactivate SARS-CoV-2 virus, lyse the cells, disrupt/lyse the lipid membranes and denature proteins for storage of the specimen between 39 °F and 73 °F (4 °C - 23 °C). The media is sold in the following configurations.
- A plastic screw-cap tube filled with 3 mL of Dasky Disposable Sampling Tube media.
- A plastic screw-cap tube filled with 3 mL of Dasky Disposable Sampling Tube media and a NP nylon flocked swab for sample collection.
### B Principle of Operation:
The Dasky Disposable Sampling Tube (Model name: VSM02) contains nucleic acid preservation media, which contains a high concentration of guanidinium salt and nucleic acid stabilizer. After the collected virus sample is thoroughly mixed with the media, the virus (or other pathogens) will be rapidly inactivated, lysed and the nucleic acid will be released. Nucleic acid stabilizers in the liquid protect the released nucleic acids (RNA) from degradation by RNase. The specimen processed by this collection tube can be used with compatible nucleic acid extraction and amplification platforms.
The media contains the following reagents:
- Tris
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- Protease K
- Guanidine hydrochloride
- Dithiothreitol
- Triton X-100
- Distilled water
V Substantial Equivalence Information:
A Predicate Device Name(s): DNA/RNA Shield Collection Tube
B Predicate 510(k) Number(s): K202641
C Comparison with Predicate(s):
| Device & Predicate Device(s): | Device: K211675 | Predicate: K202641 |
| --- | --- | --- |
| Device Trade Name | Dasky Disposable Sampling Tube (Model name: VSM02) | DNA/RNA Shield Collection tube |
| General Device Characteristic Similarities | | |
| Intended Use/Indications For Use | The Dasky Disposable Sampling Tube (Model name: VSM02) is intended for the stabilization, transportation and inactivation of infectious unprocessed nasopharyngeal specimen samples suspected of containing SARS-CoV-2. These devices can be used for collection transport and storage of specimens from the collection site to the laboratory. The specimens collected and stored in a Dasky Disposable Sampling Tube (Model name: VSM02) are suitable for use with compatible laboratory based molecular diagnostic devices. | The DNA/RNA Shield collection tube is intended for the stabilization and inactivation of upper and lower respiratory human specimens suspected of containing SARS-CoV-2. These devices can be used for collection transport and storage of specimens at ambient temperatures (20-25°C). Specimens collected and stored in a DNA/RNA Shield collection tube are suitable for use with legally marketed molecular diagnostic devices. |
| Microorganism nucleic acids preserved | Same | SARS-CoV-2 |
| Container | Same | Tube, plastic, screw cap vials |
| Medium Volume | 3 mL | 1 mL, 2 mL |
| Special conditions for use | Same | 1. For in vitro diagnostic use only
2. For Prescription Use only |
| Sample source | Same | Human respiratory |
| General Device Characteristic Differences | | |
| RNA stabilization at refrigeration | 144 hours (4°C) | no refrigeration claims |
| RNA | 48 hours (23°C) | 28 days |
K211675 - Page 3 of 7
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| stabilization
at ambient temperature | | |
| --- | --- | --- |
| Specimen Type | Nasopharyngeal specimens for SARS-CoV-2. | Lower and Upper Respiratory
Specimens for SARS-CoV-2. |
| Analyte | RNA | RNA and DNA |
| Shelf life | 1 year | 2 years |
VI Standards/Guidance Documents Referenced:
Special controls that are applicable to regulation 21 CFR 866.2950.
VII Performance Characteristics (if/when applicable):
A Analytical Performance:
1. Traceability, Stability, Expected Values (Controls, Calibrators, or Methods):
Shelf life: The Shelf-life for the Dasky Disposable Sampling Tube (Model name: VSM02) is 1 year after the date of manufacture. The stability of the Dasky Disposable Sampling Tube (Model name: VSM02) was performed using Realtime stability study on a total of 9 samples (3 Lots). The item appearance inspection, pH detection, RT-PCR test, virus inactivation efficiency detection and Limit of detection are considered as the factor of evaluation.
Sterilization: The Dasky Disposable Sampling Tube (Model name: VSM02) with media are not sold as sterile nor are they intended to be sterilized by the user. These vials are single use devices that do not require cleaning by the operator.
2. Detection Limit:
a) LoD
The detection limit of SARS-CoV-2 nucleic acid (RNA) in 3 mL media in the Dasky Disposable Sampling Tube (Model name: VSM02) was determined. The detection limit concentration was verified to ensure that SARS-CoV-2 RNA could be repeatedly recovered from the disposable sample tube at the lowest detection concentration with an accuracy greater than 95%.
LoD testing was conducted by spiking multiple volume of SARS-CoV-2 virus with a titer of 10⁵ Genomic Copy Equivalents (GCE)/mL (determined by real-time qPCR) into clinical NP swab matrix collected from individuals who tested negative for SARS-CoV-2, and then using the NP swab to transfer the virus sample into 3 mL of media in the Dasky Disposable Sampling Tube (Model name: VSM02) to achieve the final concentration of 63 GCE/mL, 70 GCE/mL, 1×10² GCE/mL, 3×10² GCE/mL, 1×10³ GCE/mL and 1×10⁴ GCE/mL, for each of the 20 tubes/lot for three lot.
Purified RNA was extracted from 200 μL samples by using MagMAX Viral/Pathogen Nucleic Acid Isolation Kit manufactured by Thermo Scientific. RT-PCR was performed
K211675 - Page 4 of 7
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on the ABI7500 using the EUA-authorized TaqPath COVID-19 Combo kit of Thermo Scientific.
$\sim 78\%$ detection (viral targets $C_t$ values are $< 37$ ) of the SARS-CoV-2 RNA was observed in samples at 63 GCE/mL (16/60 replicates). The detection of the SARS-CoV-2 at all other higher concentrations: $1 \times 10^4$ GCE/mL, $1 \times 10^3$ GCE/mL, $3 \times 10^2$ GCE/mL, $1 \times 10^2$ GCE/mL and 70 GCE/mL resulted in 60/60 replicates. The LoD testing results are summarized in Table 1:
Table 1. LoD testing
| GCE/mL | Total # | Positive # | Mean Ct | | |
| --- | --- | --- | --- | --- | --- |
| | | | ORF1ab | N gene | S gene |
| 104 | 60 | 60 | 20.94 | 21.08 | 21.04 |
| 103 | 60 | 60 | 24.23 | 23.99 | 24.12 |
| 3x 102 | 60 | 60 | 26.70 | 26.95 | 26.93 |
| 102 | 60 | 60 | 29.95 | 30.04 | 30.29 |
| 70 | 60 | 60 | 32.84 | 32.82 | 33.94 |
| 63 | 60 | 47 | 36.13 | 36.04 | 35.89 |
In summary, the LoD testing at 70 GCE/mL resulted in 60/60 replicates for NP swabs, which meet the pre-defined acceptance criteria for NP swabs.
# b) Specimen stability
The specimen stability study was conducted by spiking $4.5\mu \mathrm{L}$ of SARS-CoV-2 virus at $1\times 10^{5}$ GCE/mL into the clinical NP swab specimen collected from individuals who tested negative for SARS-CoV-2, then using the NP swab to transfer the virus sample into the Dasky Disposable Sampling Tube (Model name: VSM02) containing $3\mathrm{mL}$ media to achieve the final concentration of the samples at $150\mathrm{GCE / mL}$ (2.1x LoD).
Three Dasky Disposable Sampling Tube (Model name: VSM02) of each lot (Lot 20100732-01, Lot 21060732-02 and Lot 21121032-01) were tested by RT-PCR and served as $\mathrm{T_0}$ ; The measured $\mathrm{C_t}$ values for the samples stored at $23^{\circ}\mathrm{C}$ for at least 48 hours or at $4^{\circ}\mathrm{C}$ for at least 144 hours and were defined as $\mathrm{T}_{23\rightarrow 48}$ and $\mathrm{T}_{4\rightarrow 144}$ , respectively. Purified RNA was extracted from $200~\mu \mathrm{L}$ samples by MagMAX Viral/Pathogen Nucleic Acid Isolation Kit manufactured by Thermo Scientific. RT-PCR was performed on the ABI7500 using the EUA-authorized TaqPath COVID-19 Combo kit of Thermo Scientific. The deviation between $\mathrm{C_t}$ measurement value and initial $\mathrm{C_t}$ measurement value of different storage time is less than 2. The results for the specimen stability study are summarized in Table 2.
Table 2. Specimen Stability
| Lot No. | Storage condition | Replicate | Ct | | | Interpretation | % Positive |
| --- | --- | --- | --- | --- | --- | --- | --- |
| | | | ORF1ab | N gene | S gene | | |
| 20100732-01 | T0 | 1 | 28.6 | 28.7 | 28.4 | Positive | 100% |
| | | 2 | 29.7 | 29.6 | 29.2 | Positive | |
| | | 3 | 28.3 | 28.2 | 28.1 | Positive | |
K211675 - Page 5 of 7
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| | T23->48 | 1 | 30.9 | 30.1 | 30.3 | Positive |
| --- | --- | --- | --- | --- | --- | --- |
| | | 2 | 30.5 | 30.9 | 29.8 | Positive |
| | | 3 | 29.9 | 29.3 | 29.9 | Positive |
| | T4->144 | 1 | 29.0 | 29.4 | 29.0 | Positive |
| | | 2 | 30.7 | 30.1 | 29.5 | Positive |
| | | 3 | 29.8 | 30.1 | 30.9 | Positive |
| 21060732-02 | T0 | 1 | 29.1 | 29.2 | 28.8 | Positive |
| | | 2 | 29.0 | 30.5 | 29.8 | Positive |
| | | 3 | 28.3 | 28.7 | 29.6 | Positive |
| | T23->48 | 1 | 29.2 | 28.9 | 29.8 | Positive |
| | | 2 | 29.4 | 29.8 | 30.5 | Positive |
| | | 3 | 28.5 | 29.6 | 29.9 | Positive |
| | T4->144 | 1 | 29.8 | 29.5 | 29.0 | Positive |
| | | 2 | 29.2 | 29.0 | 29.5 | Positive |
| | | 3 | 30.2 | 30.5 | 30.9 | Positive |
| 21121032-01 | T0 | 1 | 28.1 | 28.9 | 29.7 | Positive |
| | | 2 | 29.8 | 28.7 | 28.3 | Positive |
| | | 3 | 28.1 | 29.5 | 29.8 | Positive |
| | T23->48 | 1 | 30.0 | 30.9 | 29.7 | Positive |
| | | 2 | 29.3 | 29.8 | 28.7 | Positive |
| | | 3 | 29.0 | 28.3 | 29.5 | Positive |
| | T4->144 | 1 | 29.4 | 29.0 | 29.3 | Positive |
| | | 2 | 29.1 | 29.4 | 29.6 | Positive |
| | | 3 | 29.4 | 29.3 | 29.1 | Positive |
The deviation between the initial $C_t$ measurement value and the $C_t$ measurement value of samples stored at either $23^{\circ}\mathrm{C}$ for a minimum of 48 hours or $4^{\circ}\mathrm{C}$ for a minimum of 144 hours is less than $2C_t$ . The results demonstrated acceptable RNA stabilization at $23^{\circ}\mathrm{C}$ for 48 hours or $4^{\circ}\mathrm{C}$ for 144 hours.
c) Inactivation
Three batches of the Dasky Disposable Sampling Tube (Model name: VSM02) were used for inactivation assessment. In the experimental group, $30~\mu \mathrm{L}$ SARS-CoV-2 virus at $1\times 10^{5}$ GCE/mL was added to clinical NP swab specimen collected from individuals who tested negative for SARS-CoV-2 virus, and then then using the NP swab to transfer the virus sample into the Dasky Disposable Sampling Tube (Model name: VSM02) containing $3\mathrm{mL}$ of media to achieve $1\times 10^{3}$ GCE/mL. In the control group, $30~\mu \mathrm{L}$ SARS-CoV-2 virus with a titer of $1\times 10^{5}$ GCE/mL was added to clinical NP swab specimen collected from individuals who tested negative for SARS-CoV-2, and then then using the NP swab to transfer the virus sample into $3\mathrm{mL}$ PBS (phosphate buffered saline). The experimental group and the control group were incubated at room temperature for five (5) minutes. After 5 minutes, the samples of the experimental group and the control group were diluted 1:1000 with ultrapure water; $30~\mu \mathrm{L}$ of diluted samples from the experimental group and control group were used to infect Vero-E6 cells (the cells were grown in a 96-well plates for 24 hours. prior to infection). After 4 days of infection, the morphology of
K211675 - Page 6 of 7
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the cells was observed under an electron microscope to determine the cytological changes. By observing the cell morphology of the infected Vero-E6 cells, it was found that the virus in the control group could infect Vero-E6 cells. For the experimental group, the virus was inactivated and was no longer able to infect Vero-E6 cells after exposure to the media in the Dasky Disposable Sampling Tube (Model name: VSM02) for 5 minutes. The intact morphology of the cells could be observed under the microscope. The results for the specimen stability study were summarized in Table 3.
Table 3. Virus inactivation assessment
| Sample type (SARS-CoV-2 virus at 1x 103 GCE/mL) | Test number | LOT No. | | |
| --- | --- | --- | --- | --- |
| | | 20100732-01 | 21060732-02 | 21121032-01 |
| | | Inactivation results | | |
| Experimental group | 1# | uninfected | uninfected | uninfected |
| | 2# | uninfected | uninfected | uninfected |
| | 3# | uninfected | uninfected | uninfected |
| Control group | 1# | infected | infected | infected |
In the Inactivation efficiency test, three lots of media in the Dasky Disposable Sampling Tube (Model name: VSM02) were evaluated. For the SARS-CoV-2 virus at the concentration of $1 \times 10^{3} \mathrm{GCE} / \mathrm{mL}$ , it can be $100\%$ inactivated at a minimum of 5 minutes in the Dasky Disposable Sampling Tube (Model name: VSM02).
# VIII Proposed Labeling:
The labeling supports the finding of substantial equivalence for this device.
# IX Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.
K211675 - Page 7 of 7
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