(28 days)
The Xpert® FII & FV test is a qualitative in vitro diagnostic genotyping test for the detection of Factor V alleles from sodium citrate or EDTA anticoagulated whole blood. The test is performed on the GeneXpert® Instrument Systems. This test is intended to provide results for Factor II (G20210A) and Factor V Leiden (G1691A) mutations as an aid in the diagnosis in individuals with suspected thrombophilia.
Xpert FII & FV is an automated genotyping test for detecting Factor II and Factor V normal and mutant alleles directly from sodium citrate or EDTA anticoagulated whole blood specimens. Blood specimens are drawn into either sodium citrate or EDTA anticoagulant tubes. Following brief mixing of the sample. 50 uL of the blood sample is transferred to the bottom wall of the Sample opening of the Xpert FII & FV test cartridge. The user initiates a test from the system user interface and places the cartridge into the GeneXpert Instrument System.
The Xpert FII & FV test includes reagents for the detection of Factor II and Factor V normal and mutant alleles. The primers and probes in the Xpert FII & FV test determine the genotype of the Factor II gene (at position 20210) and/or the Factor V gene (at position 1691). The test includes a Sample Processing Control (SPC) to confirm adequate processing and to monitor the presence of inhibitor(s) in the PCR assay. The Probe Check Control (PCC) verifies reagent rehydration, PCR tube filling in the cartridge, probe integrity, and dye stability.
The GeneXpert Instrument Systems family is comprised of GeneXpert Dx System, GeneXpert Infinity System, and GeneXpert System with Touchscreen. The GeneXpert Instrument Systems automate and integrate sample processing, nucleic acid amplification and detection of the target sequences in simple or complex samples using real-time polymerase chain reaction (PCR). The systems consist of an instrument, computer or touchscreen, and preloaded software for running the tests and viewing the results. The GeneXpert Instrument Systems require the use of singleuse disposable cartridges that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained, cross-contamination between samples is minimized.
The GeneXpert Instrument Systems have 1 to 80 modules (depending upon the instrument) that are each capable of performing separate sample preparation and real-time PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores, and a proprietary I-CORE® thermocycler for performing real-time PCR and detection.
The Xpert FII & FV test performed on the GeneXpert Instrument Systems provides results in approximately 30 minutes.
This document is a 510(k) summary for the Xpert FII & FV diagnostic test, seeking to remove a limitation statement and make minor branding/catalog number changes. It does not contain a study explicitly detailing acceptance criteria and performance against those criteria for the current submission. Instead, it refers to prior clearance (K082118) for the clinical validation supporting the removal of the limitation statement, and asserts that the current changes do not impact performance.
Therefore, the following information is extracted or inferred based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance:
The document explicitly states: "No new performance data were provided in this submission." The basis for substantial equivalence relies on the device being identical to its predicate (K223046) in all technological characteristics relevant to performance. The one significant change (removal of the pediatric patient limitation) is supported by prior clinical validation data (K082118). Since no new performance data or acceptance criteria are presented for this specific submission, this table cannot be fully completed from the provided text.
However, based on the nature of a genetic mutation detection system, typical acceptance criteria would involve analytical sensitivity, analytical specificity, and clinical performance (e.g., concordance with a gold standard). Without the original K082118 submission, specific numerical criteria are not available.
| Acceptance Criteria Category | Specific Acceptance Criteria (Inferred/Generic for Genetic Tests) | Reported Device Performance (Implied from Substantial Equivalence and Prior Clearance) |
|---|---|---|
| Analytical Performance | Precision (reproducibility across runs, lots) | Not explicitly stated in this document; implied to meet prior clearance standards. |
| Reproducibility (inter-site, inter-operator) | Not explicitly stated in this document; implied to meet prior clearance standards. | |
| Genotyping Accuracy (Concordance with reference method) | Not explicitly stated in this document; implied to meet prior clearance standards, as the test is based on PCR. | |
| Limit of Detection | Not explicitly stated in this document; implied to meet prior clearance standards. | |
| Interference | Not explicitly stated in this document; implied to meet prior clearance standards. | |
| Clinical Performance | Clinical Sensitivity (ability to detect mutation when present) | Not explicitly stated in this document; implied to meet prior clearance standards with sufficient accuracy for diagnosis. |
| Clinical Specificity (ability to correctly identify absence of mutation) | Not explicitly stated in this document; implied to meet prior clearance standards with sufficient accuracy for diagnosis. | |
| Overall Concordance with Gold Standard | The performance was previously validated in clinical studies (K082118) and deemed acceptable to aid in diagnosis. | |
| Robustness/System Performance | SPC/PCC performance | SPC confirms adequate processing and monitors inhibitors; PCC verifies reagent integrity. Performance implicitly meets design requirements. |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not explicitly stated in this document. The document refers to "clinical validation data that was submitted and reviewed as part of the original device clearance (K082118)" as the basis for removing the pediatric limitation. The sample size for that original study is not provided here.
- Data Provenance: Not explicitly stated in this document. Given it's a 510(k) for a US market device, it is likely the original clinical validation (K082118) included US data, but this is not confirmed. It refers to "clinical validation data," which typically implies prospective collection of patient samples.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
- Not explicitly stated in this document. This level of detail would typically be found in the original clinical validation report (K082118). For genotyping, ground truth is usually established by orthogonal molecular methods, not primarily by expert consensus in the same way as imaging or pathology interpretation.
4. Adjudication Method for the Test Set:
- Not applicable/Not mentioned. For genetic tests where the ground truth is often established through well-defined molecular techniques (e.g., Sanger sequencing or a validated reference method), adjudication by multiple experts in the traditional sense (like for imaging reads) is generally not performed. The ground truth is objective.
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 is relevant for interpretive tasks (e.g., radiologists reading images) where human performance is being evaluated and compared with and without AI assistance. The Xpert FII & FV is an automated genotyping test; it does not involve human readers interpreting results in the same manner.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, the performance characteristics mentioned (e.g., analytical sensitivity, specificity) for a molecular diagnostic test like the Xpert FII & FV are inherently "standalone" in nature. The device itself performs the assay and provides a qualitative genotype call. The results are automated and interpreted by the diagnostic software.
7. The Type of Ground Truth Used:
- Not explicitly stated in this document, but for genetic tests, the ground truth is typically established by orthogonal molecular methods, such as Sanger sequencing or another highly accurate, validated reference genotyping method. It is not based on expert consensus, pathology, or outcomes data in the way these terms are typically used for imaging or disease diagnosis.
8. The Sample Size for the Training Set:
- Not explicitly stated in this document. The device uses real-time PCR for detection, and while there might be algorithm tuning within the software, the foundational "training" often refers to the design and optimization of primers and probes, and establishment of cut-offs, rather than machine learning on a large training set of clinical samples. The document refers to "clinical validation data" for performance, but not specifically to a training set size for an algorithm.
9. How the Ground Truth for the Training Set was Established:
- Not explicitly stated in this document. This would be part of the original developmental studies for the device (predating K082118). For a PCR-based test, ground truth for developing and optimizing the assay would involve samples with known genotypes confirmed through reference methods.
§ 864.7280 Factor V Leiden DNA mutation detection systems.
(a)
Identification. Factor V Leiden deoxyribonucleic acid (DNA) mutation detection systems are devices that consist of different reagents and instruments which include polymerase chain reaction (PCR) primers, hybridization matrices, thermal cyclers, imagers, and software packages. The detection of the Factor V Leiden mutation aids in the diagnosis of patients with suspected thrombophilia.(b)
Classification. Class II (special controls). The special control is FDA's guidance entitled “Class II Special Controls Guidance Document: Factor V Leiden DNA Mutation Detection Systems.” (See § 864.1(d) for the availability of this guidance document.)