(133 days)
The ID Biomedical Velogene™ Rapid MRSA Identification Assay is intended as a qualitative assay for the definitive identification of methicillin resistance in presumptively identified cultures of Staphylococcus aureus by detecting the presence of the mecA gene. The presence of the mecA gene confers resistance to methicillin.
The Velogene™ Rapid MRSA Identification Assay is a DNA probe based diagnostic device that is based on Cycling Probe™ Technology (CPT) to generate spectrophotometric or visual results. The assay consists of two reagent kits, MRSA Lysis/Cycle Kit and MRSA Microwell Detection Kit.
Here's a breakdown of the acceptance criteria and study details for the Velogene™ Rapid MRSA Identification Assay, based on the provided text:
Acceptance Criteria and Device Performance
The primary acceptance criterion is substantial equivalence to the predicate device, the Oxacillin Screen Agar (NCCLS approved test for MRSA detection). This substantial equivalence is demonstrated through high agreement in identifying methicillin resistance in S. aureus samples.
| Acceptance Criteria Category | Acceptance Criteria (Implicit) | Reported Device Performance (Velogene™ Rapid MRSA Identification Assay) |
|---|---|---|
| Overall Agreement with Predicate Device | High agreement with Oxacillin Screen Agar in clinically relevant S. aureus samples. | 99.3% agreement (420/423) in routine clinical samples. |
| Reproduction of MRSA Results | High reproducibility for MRSA results. | 99.8% (449/450) reproducible for MRSA (OD650 ≤ 0.18, Visual: Clear). |
| Reproduction of MSSA Results | High reproducibility for MSSA results. | 99.8% (449/450) reproducible for MSSA (OD650 > 0.18), 100% (450/450) visual reproducibility. |
| Analytical Sensitivity (MRSA) | Detect MRSA at clinically relevant concentrations. | Detects 93.75 x 10 to 375 x 10 MRSA CFU/reaction (OD650 0.18) similar to an "algorithm only" interpretation, visual interpretation is also an option, implying a human-in-the-loop component for some results. However, the performance data presents both spectrophotometric and visual results as highly concordant, suggesting objective interpretation is a primary mode. The PCR results validating discrepancies are also a standalone, objective measure. |
7. The type of ground truth used:
- Primary Ground Truth for Clinical Comparison: The Oxacillin Screen Agar (a NCCLS approved test for MRSA detection) served as the primary comparative ground truth.
- Definitive Ground Truth for Discrepancy Resolution: nuc/mecA PCR was used as the definitive ground truth for the 3 discrepant isolates, confirming the presence or absence of the mecA gene. This is a molecular/pathology-based ground truth.
- Analytical Sensitivity/Specificity/Reproducibility: Used defined control strains (S. aureus ATCC 29213 - mecA negative, S. aureus ATCC 33592 - mecA positive) and specific isolates for analytical specificity testing. These are laboratory-defined ground truths.
8. The sample size for the training set:
The document describes performance evaluation studies and does not explicitly mention a dedicated training set or its sample size. This is common for traditional diagnostic assays where performance is validated against established methods and/or molecular gold standards, rather than "trained" like machine learning models. The study focuses on validation of the assay.
9. How the ground truth for the training set was established:
As no explicit training set is described, this question is not applicable. The assay's principles are based on known molecular biology (detection of the mecA gene).
§ 866.1640 Antimicrobial susceptibility test powder.
(a)
Identification. An antimicrobial susceptibility test powder is a device that consists of an antimicrobial drug powder packaged in vials in specified amounts and intended for use in clinical laboratories for determining in vitro susceptibility of bacterial pathogens to these therapeutic agents. Test results are used to determine the antimicrobial agent of choice in the treatment of bacterial diseases.(b)
Classification. Class II (performance standards).