(575 days)
The ARX Liquid Amies Collection & Transport System (ARX) is intended for use in the collection of clinical specimens (i.e., nasal secretion/wash; lachrymal secretion/tears; auricular secretion/cerumen; urethral, rectal, or vaginal swab; wound/abscess material) potentially containing aerobic, and fastidious bacteria and their transport at 2-8°C or 25-30°C from the patient to the laboratory for bacteriological examination and culture. In the laboratory, the collected and transported clinical specimens of nasal, lachrymal, ceruminous, vaginal, urethral, rectal, and wound/abscess origin are processed using standard clinical laboratory operating procedures for bacterial culture.
The ARX Liquid Amies Collection & Transport System consists of a polypropylene screw-cap vial containing Liquid Amies transport medium and three (3) sterile peel-open pouches containing a pre-scored Microbrush nylon flocked swab for collecting specimens. The three (3) nylon flocked swabs are provided with various score points, tip sizes, and configurations to facilitate specimen collection from various sites on patients' bodies. Nylon flocked swabs facilitate quick absorption and release of clinical specimens. Proper specimen collection from the patient is critical for successful isolation and identification of infectious organisms.
Amies liquid medium is a non-nutritive balanced salt solution containing inorganic phosphates to provide buffering capability, sodium chloride, potassium chloride, and magnesium chloride to provide essential ions that help maintain osmotic balance and control permeability of bacterial cells. It also contains sodium thioglycolate to provide a reduced environment. ARX Liquid Amies transport medium is capable of maintaining the viability of aerobic, anaerobic, and fastidious bacteria (such as Neisseria gonorrhoeae) during specimen transport to the laboratory for bacteriological testing and culture.
All raw materials used in the manufacture of ARX Liquid Amies Collection & Transport System are qualified before use. Every batch of ARX Liquid Amies Collection & Transport System is tested prior to release for sterility, pH, and background count using microscopic examination. Representative samples of each batch are further evaluated for their ability to maintain the viability of selected bacterial agents over predefined time periods.
The provided text describes the performance characteristics of the ARX Liquid Amies Collection & Transport System for bacterial recovery. This information is relevant to the acceptance criteria and the study proving the device meets these criteria.
Here's an analysis of the provided information to address your request:
Device: ARX Liquid Amies Collection & Transport System
Purpose of Study: To demonstrate the ability of the device to maintain the viability of aerobic, anaerobic, and fastidious bacteria during specimen transport, and to establish shelf-life stability.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for bacterial recovery are stated as:
- Roll-Plate studies: Minimum acceptable viability of at least 2% CFU relative to time 0.
- Swab Elution studies: Maximum 3 log10 decline in CFU acceptable relative to time 0.
For shelf-life stability:
- pH within specified range (7.30 ± 0.2).
- Visual inspection (no turbidity).
- Viscosity within specified range (1.075 ± 0.015 milliPascal.Second).
Table: Acceptance Criteria and Reported Device Performance (Summary)
| Performance Characteristic | Acceptance Criteria | Reported Device Performance (Overall Conclusion) |
|---|---|---|
| Bacterial Recovery | ||
| Roll-Plate Method | Minimum 2% CFU viability relative to Time 0 for all organisms (N. gonorrhoeae: 24 hrs; others: 48 hrs). | Met: "the performance of all bacterial recovery, when used with or without NCM, was found to be acceptable." (Tables 3-6 provide detailed CFUs validating this). |
| Swab Elution Method | Maximum 3 Log10 decline in CFU relative to Time 0 for all organisms (N. gonorrhoeae: 24 hrs; others: 48 hrs). | Met: "the performance of all bacterial recovery, when used with or without NCM, was found to be acceptable." (Tables 7-10 provide detailed Log10 changes validating this, with all values less than 3 log10 decline). |
| Shelf-Life Stability | ||
| pH monitoring | pH within 7.30 ± 0.2 | Met: Maintained pH within specified range for 18 months. |
| Visual estimation of turbidity | Pass visual inspection | Met: Passed visual inspection for 18 months. |
| Viscosity measurement | Viscosity within 1.075 ± 0.015 milliPascal.Second | Met: Maintained viscosity within specified range for 18 months. |
Conclusion from non-clinical Performance Studies: "the ARX Liquid Amies Collection & Transport System showed recovery of bacteria within the acceptance criteria comparable to the predicate device for all holding temperatures tested. This demonstrates the acceptability claim of up to 48 hours for all organisms (except 24 hours for Neisseria gonorrhoeae) in clinical samples during storage and/or transport in this transport system. Additional studies conducted with the ARX Liquid Amies Collection & Transport System support the shelf-life stability claim of 18 months."
2. Sample Size Used for the Test Set and Data Provenance
The "test set" in this context refers to the bacterial strains and conditions used for the performance studies, not a patient-derived dataset.
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Sample Size (Test Set):
- Bacterial Strains: A total of 17 bacterial strains were used:
- 3 aerobic bacteria
- 6 facultative anaerobic bacteria (including 1 fastidious organism, Neisseria gonorrhoeae)
- 8 obligate anaerobic bacteria (listed in Table 2)
- Device Samples: For each study (Roll-Plate and Swab Elution, with NCM and Saline at different temperatures):
- 3 independent lots of ARX Liquid Amies (Old, Middle-aged, New) were tested.
- For each combination of organism, lot, and temperature/matrix, the swabs were inoculated in triplicate.
- Measurements were taken at 0, 24, and 48 hours (except N. gonorrhoeae only at 24 hours).
- Shelf-life Stability: 4 manufactured lots were evaluated.
- Bacterial Strains: A total of 17 bacterial strains were used:
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Data Provenance: The data appears to be from controlled laboratory studies (prospective experimental data) conducted to validate the device's performance. The document does not specify a country of origin for the data, but given it's an FDA submission, it's typically either conducted in the US or in adherence to international standards acceptable to the FDA. The matrices used were "Negative Clinical Matrix (NCM) or sterile saline," simulating clinical conditions.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This type of device (microbiological specimen collection and transport system) relies on established microbiological laboratory standards and quantitative measurements (CFU counts) rather than subjective expert interpretation of medical images or pathologies. Therefore, there is no mention of "experts" in the traditional sense (e.g., radiologists) establishing ground truth. The "ground truth" here is determined by the live cultures and their measured viability, following universally accepted laboratory protocols.
- Number of Experts: Not applicable in the context of expert consensus for ground truth on images or clinical outcomes.
- Qualifications of Experts: Not applicable. The "ground truth" (bacterial viability) is established by direct laboratory measurements following CLSI M40-A2 standards.
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are typically used in clinical studies where multiple human readers or algorithms provide interpretations, and a consensus or higher-level review is needed to establish a definitive ground truth.
For this device, the "ground truth" is based on direct quantitative laboratory measurements (colony forming unit counts) of bacterial viability. These are objective measures, not subjective interpretations. Therefore:
- Adjudication Method: Not applicable. Ground truth is derived from direct quantitative microbiological assays.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
MRMC studies are typically performed for diagnostic devices (e.g., AI-powered imaging systems) where human interpretation plays a role, and the goal is to assess how a new technology impacts diagnostic performance.
This device is a specimen collection and transport system, not a diagnostic imaging or AI-driven interpretive tool. The study focuses on the physical and biological performance of the transport medium and swabs in maintaining bacterial viability.
- MRMC Study: No, an MRMC study was not done as it is not relevant for this type of device.
- Effect Size of Human Readers: Not applicable.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The concept of "standalone performance" typically refers to the performance of an AI algorithm independent of human intervention. This device is not an AI algorithm. Its performance is inherent to its physical and biological properties.
- Standalone Performance: Not applicable. This is not an AI device. The studies conducted evaluate the intrinsic performance of the device itself (transport medium and swabs) in preserving bacterial samples.
7. The Type of Ground Truth Used
- Type of Ground Truth: The ground truth for the performance studies was bacterial viability/colony counts (CFU) established through controlled laboratory experiments. This is a direct, quantitative measure of the device's ability to preserve the bacteria. The studies followed FDA-recognized sections of Clinical Laboratory Standards Institute (CLSI) M40-A2:2014 Quality Control of Microbiological Transport Systems.
8. The Sample Size for the Training Set
This device is not an AI/ML device, and therefore does not have a "training set" in the computational sense. The studies described are validation and performance testing, not model training.
- Sample Size for Training Set: Not applicable, as this is not an AI/ML device.
9. How the Ground Truth for the Training Set Was Established
As there is no training set for this device in the context of AI/ML, this question is not applicable. The device's performance is based on its material properties and chemical composition, validated through standard microbiology testing.
- How Ground Truth for Training Set Was Established: Not applicable.
§ 866.2900 Microbiological specimen collection and transport device.
(a)
Identification. A microbiological specimen collection and transport device is a specimen collecting chamber intended for medical purposes to preserve the viability or integrity of microorganisms in specimens during storage of specimens after their collection and during their transport from the collecting area to the laboratory. The device may be labeled or otherwise represented as sterile. The device aids in the diagnosis of disease caused by pathogenic microorganisms.(b)
Classification. Class I (general controls). The device, when solely intended for use in the collection of concentrated parasites from specimens and transport, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 866.9.