(433 days)
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 Dasky Disposable Sampling Tube (Model name: VSM02) consists of a plastic transport tube with medium 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 media are intended to inactivate SARS-CoV-2 virus, lyse the cells, disruptlyse 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.
This response is based on the provided text.
1. Table of Acceptance Criteria and Reported Device Performance
| Test | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Limit of Detection (LoD) | SARS-CoV-2 RNA could be repeatedly recovered with an accuracy >95% | At 70 GCE/mL, 60/60 replicates were positive for all three lots (100% detection). At 63 GCE/mL, 47/60 replicates were positive (78% detection). The report states that the LoD at 70 GCE/mL meets the pre-defined acceptance criteria for NP swabs. |
| Specimen Stability (Ambient) | Acceptable RNA stabilization; deviation in Ct values ₄₈, T₄->₁₄₄) across 3 lots, for a total of 27 samples tested in the stability study (9 per lot * 3 time points). |
* **Data Provenance:** Clinical NP swab specimens collected from individuals who tested negative for SARS-CoV-2 virus. (Country of origin not specified, but the applicant company is based in China.)
- Inactivation: 3 experimental samples per lot and 1 control sample per lot across 3 lots.
- Data Provenance: Clinical NP swab specimens collected from 9 healthy individuals who tested negative for SARS-CoV-2 virus (for the experimental group). The virus itself was spiked. (Country of origin not specified, but the applicant company is based in China.)
- Shelf-life: 9 samples (3 lots)
- Data Provenance: Not explicitly detailed beyond being "Realtime stability study" using manufactured devices.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
The document does not specify the use of experts to establish ground truth for the test set.
- For LoD and Specimen Stability, ground truth was established by spiking known concentrations/titers of SARS-CoV-2 virus into negative clinical NP swab specimens and then evaluating its detection by RT-PCR.
- For Inactivation, ground truth was established by observing cytological changes in Vero-E6 cells after exposure to the treated virus, comparing experimental (inactivated) to control (non-inactivated) samples.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method involving experts for any of the test sets. The determination of positive/negative and Ct values for LoD and stability was quantitative via RT-PCR. Inactivation was determined by observing cell morphology under an electron microscope, comparing treated samples to controls.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This device is a microbial nucleic acid storage and stabilization device, not an imaging or diagnostic device that typically involves human readers. The performance studies evaluate the device's ability to preserve and inactivate the virus, assayed by laboratory methods.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies described are standalone performance evaluations of the device (Dasky Disposable Sampling Tube (Model name: VSM02)) itself, without a human-in-the-loop component in terms of interpretive performance. The device's function is to stabilize, transport, and inactivate samples, not to
diagnose or interpret.
7. The Type of Ground Truth Used
- For LoD and Specimen Stability: Spiked samples with known concentrations/titers of SARS-CoV-2 virus into clinical NP swab specimens confirmed to be negative for SARS-CoV-2. This combines a known viral load (synthetic representation of infection) with clinical matrix. Detection was via RT-PCR, providing a quantitative ground truth (Ct values).
- For Inactivation: Live SARS-CoV-2 virus spiked into negative clinical NP swab specimens, followed by incubation in the device medium or control (PBS). The ground truth for inactivation was determined by measuring the ability of the treated samples to infect Vero-E6 cells, which is a direct measure of viral viability/infectivity (viability/infection outcome data).
8. The Sample Size for the Training Set
The document does not describe a training set. This is a medical device for sample collection and stabilization, not an AI or machine learning algorithm that typically requires a training set.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as no training set is described for this device.
§ 866.2950 Microbial nucleic acid storage and stabilization device.
(a)
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.(b)
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.