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MedSchenker Smart Transport Medium (STM15-A/STM20-A/SCS30-A) System is intended for the collection and transport of upper respiratory clinical specimens, contaming respiratory viruses, from the collection site to the testing laboratory.
MedSchenker Smart Transport Medium (STM15-A/STM30-A/SCS30-A) System is a culture-based medium that can be processed using standard clinical laboratory operating procedures for the recovery of infectious viral particles.
The MedSchenker Smart Transport Medium (STM15-A/STM20-A/STM30-A/SCS30-A) System ("MedSchenker STM") aids in the collection and safe transportation of biological samples that will be tested for viruses. MedSchenker Smart Transport Medium (STM15-A/STM30-A/SCS30-A) System provides a universal transport medium for viruses. MedSchenker Smart Transport Medium (STM15-A/STM20-A/STM30-A/SCS30-A) System includes a universal transporting medium that is room temperature stable, which can sustain infectivity of a plurality of clinically important viruses during transit to the testing laboratory. The formulation of the STM includes protein for stabilization, antimicrobial agents to minimize bacterial and fungal contamination, and a buffer to maintain a neutral pH.
The MedSchenker Smart Transport Medium (STM15-A/STM20-A/SCS30-A) System is provided in labeled, screw-cap tubes designed for transport of the clinical sample. MedSchenker Smart Transport Medium (STM15-A/STM20-A/SCS30-A) System is also supplied as a sample collection kit that contains one screw-cap tube of STM-RT (room-temperature stable) medium and a peel pouch that contains a sterile specimen-collection swab.
The document provided describes the MedSchenker Smart Transport Medium (STM) System, a device intended for the collection and transport of upper respiratory clinical specimens containing respiratory viruses. The acceptance criteria and the study that proves the device meets these criteria are detailed, primarily through a viral recovery study.
Here's an analysis of the provided information, structured to answer your specific questions:
1. Table of Acceptance Criteria and Reported Device Performance
While explicit "acceptance criteria" for viral recovery (e.g., minimum percentage recovery) are not presented as a quantitative threshold in the document, the implied acceptance criterion is that the MedSchenker STM System demonstrates sufficient recovery and viability of relevant viruses over specified time periods and temperatures to support its intended use for specimen transport. The study aims to show that the viral load does not drop below a critical level that would compromise subsequent testing.
The "Performance Data" section details the reported device performance.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Maintain viability of HSV-1 in STM for transport. | HSV-1: At 4-8°C, TCID50/mL ranged from 4.77 x 10^5 (0h) to 3.32 x 10^5 (72h), with max reduction of -32.89% at 48h. At 20-25°C, TCID50/mL ranged from 4.28 x 10^5 (0h) to 2.71 x 10^5 (72h), with max reduction of -36.57% at 72h. Recovery in all replicates demonstrated at 72 hours. |
| Maintain viability of HSV-2 in STM for transport. | HSV-2: At 4-8°C, TCID50/mL ranged from 1.49 x 10^5 (0h) to 7.56 x 10^4 (72h), with max reduction of -49.24% at 72h. At 20-25°C, TCID50/mL ranged from 1.52 x 10^5 (0h) to 8.13 x 10^4 (72h), with max reduction of -46.55% at 72h. Recovery in all replicates demonstrated at 72 hours. |
| Maintain viability of Adenovirus in STM for transport. | Adenovirus: At 4-8°C, TCID50/mL ranged from 1.11 x 10^5 (0h) to 7.87 x 10^4 (72h), with max reduction of -29.33% at 72h. At 20-25°C, TCID50/mL ranged from 1.03 x 10^5 (0h) to 5.97 x 10^4 (72h), with max reduction of -41.77% at 72h. Recovery in all replicates demonstrated at 72 hours. |
| Maintain viability of VZV in STM for transport. | VZV: At 4-8°C, TCID50/mL ranged from 1.23 x 10^6 (0h) to 4.33 x 10^5 (24h), with reduction of -64.85% at 24h. At 20-25°C, TCID50/mL ranged from 1.08 x 10^6 (0h) to 1.43 x 10^6 (24h), with an increase of +32.13% at 24h. Recovery in all replicates demonstrated at 24 hours. |
| Maintain viability of Influenza A in STM for transport. | Influenza A: At 4-8°C, TCID50/mL ranged from 7.11 x 10^6 (0h) to 5.79 x 10^6 (24h), with reduction of -18.57% at 24h. At 20-25°C, TCID50/mL ranged from 5.52 x 10^6 (0h) to 2.21 x 10^6 (24h), with reduction of -60.00% at 24h. Recovery in all replicates demonstrated at 24 hours. |
| Support transport of specimens for mycoplasma testing. | Not Supported: "Data was insufficient to support use of this medium for transport of specimens for mycoplasma testing." This indicates a clear failure to meet an implied acceptance criterion for mycoplasma. |
| Overall conclusion of viral recovery for intended use species. | "The MedSchenker STM demonstrated the recovery of HSV-1, HSV-2, and Adenovirus in all replicates at tested incubation times and storage conditions. These data support the transportation of HSV-1, HSV-2, and Adenovirus in MedSchenker STM at refrigerated (4-8°C) or room temperature (20-25°C) for up to 72 hours. The MedSchenker STM also demonstrated the recovery of VZV and Flu A in all replicates at refrigerated (4-8°C) or room temperature (20-25°C), up to 24 hours." This statement represents the device meeting the overall implied acceptance criteria for the specified viruses and transport durations. |
2. Sample Size Used for the Test Set and Data Provenance
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Sample Size for Test Set:
- For each viral strain (HSV-1, HSV-2, Adenovirus, VZV, Flu A), "three replicates" of inoculated swabs were tested.
- These replicates were tested across two temperatures (4-8°C and 20-25°C) and multiple time points (0, 24, 48, 72 hours for HSV-1, HSV-2, Adenovirus; 0, 24 hours for Flu A and VZV).
- Each time point was assessed using "3 lots of media."
- Therefore, the total number of individual tests (replicates x temperatures x time points x lots) is substantial for each virus. For HSV-1, for example: 3 replicates x 2 temperatures x 4 time points x 3 lots = 72 tests.
- The "negative nasopharyngeal clinical matrix" was used to prepare the viral samples, indicating the use of a relevant biological sample type.
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Data Provenance: The document does not explicitly state the country of origin for the data or whether the study was retrospective or prospective. Given it is a premarket notification for an FDA submission, the data would typically be generated in a controlled laboratory setting, likely in the US or an equivalent regulatory region, and would be considered prospective for the purpose of demonstrating device performance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This type of study does not rely on expert consensus for "ground truth" in the way an AI diagnostic imaging study would. The ground truth here is the measured viral viability (TCID50/mL) determined through laboratory assays (MTT assay and observation of cytopathic effects on host cell monolayers). This is an objective, quantitative measurement rather than an interpretive one requiring expert adjudicated consensus. Therefore, the concept of "number of experts" or their qualifications for establishing ground truth is not applicable in this context. The validity of the ground truth relies on the rigor of the laboratory procedures and controls.
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are typically used in studies where human interpreters (e.g., radiologists) are making subjective judgments, and a consensus needs to be reached for the ground truth. As noted in point 3, this study involves objective laboratory measurements of viral viability (TCID50/mL) and cytopathic effects (CPE). There is no "adjudication" in the sense of reconciling differing expert opinions. The method involves conducting replicates and ensuring consistent results across those replicates and media lots.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This type of study assesses how AI assistance impacts human reader performance (e.g., radiologists interpreting images). The MedSchenker STM System is a transport medium, not an AI diagnostic tool, and therefore, an MRMC study is not relevant to its performance evaluation.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) Was Done
This question is framed for AI algorithms. Interpreting it for this device: the "standalone" performance here refers to the inherent ability of the transport medium to maintain viral viability under specified conditions, without intervention or modification based on human interpretation or real-time adjustment. The viral recovery studies (as described in section 7, "Performance Data") are precisely this: a "standalone" evaluation of the transport medium's performance in preserving viral integrity. The results (TCID50/mL and percent change) are direct measures of the medium's efficacy.
7. The Type of Ground Truth Used
The ground truth used was quantitative viral viability measurements expressed as Tissue Culture Infectious Dose 50% per milliliter (TCID50/mL) and qualitative assessment of cytopathic effects (CPE) on host cell monolayers. This is a direct measure of the infectious viral particles remaining viable in the transport medium over time compared to the initial concentration. This is an objective, laboratory-based "outcomes data" rather than expert consensus or pathology in the traditional sense from clinical samples.
8. The Sample Size for the Training Set
This question is relevant for AI/machine learning models. The MedSchenker STM system is a physical transport medium, not a software algorithm that undergoes "training." Therefore, there is no "training set" in the context of this device.
9. How the Ground Truth for the Training Set Was Established
As there is no "training set" for a physical transport medium, this question is not applicable. The device's performance is driven by its chemical composition and physical properties, which are validated through the performance studies described, not learned from data.
§ 866.2390 Transport culture medium.
(a)
Identification. A transport culture medium is a device that consists of a semisolid, usually non-nutrient, medium that maintains the viability of suspected pathogens contained in patient specimens while in transit from the specimen collection area to the laboratory. The device aids in the diagnosis of disease caused by pathogenic microorganisms and also provides epidemiological information on these diseases.(b)
Classification. Class I (general controls).