(120 days)
The eSensor® Thrombophila Risk Test is an in vitro diagnostic for the detection and genotyping of Factor II (Prothrombin) G20210A, Factor V (Factor V Leiden) G1691A and MTHFR (human 5, 10 methylenetetrahydrofolate reductase gene) C677T and A1298C mutations with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.
The eSensor® FII-FV Genotyping Test is an in vitro diagnostic for detection and genotyping of Factor II (Prothrombin) G20210A and Factor V (Factor V Leiden) G1691A mutations in patients with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.
The eSensor® FV Genotyping Test is an in vitro diagnostic for the detection and genotyping of a single point mutation (G to A at position 1691; also known as Factor V Leiden) of the human Factor V gene (FV; Coagulation Factor V gene) in patients with suspected thrombophilia from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.
The eSensor® FII Genotyping Test is an in vitro diagnostic for the detection and genotyping of a single point mutation (G to A at position 20210 of the human Factor II gene (FII; prothrombin gene) in patients with suspected thrombophilia, from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.
The eSensor® MTHFR Genotyping Test is an in vitro diagnostic for the detection and genotyping of point mutations (C to T at position 677) and (A to C at position 1298) of the human 5, 10 methylenetetrahydrofolate reductase gene (MTHFR) in patients with suspected thrombophilia, from isolated genomic DNA obtained from whole blood samples. The test is intended to be used on the eSensor® XT-8 System.
The eSensor® Thrombophila Risk Tests on the eSensor® XT-8 System are in vitro diagnostic devices for performing hybridization and genotyping of multiple mutations and/or polymorphisms in an amplified DNA sample. A single-use, disposable test carridge is used to perform hybridization and genotyping. The cartridge contains an EEPROM chip which transmits the cartridge lot number, expiration date and protocol identity to the XT-8 instrument.
The analysis process for each sample consists of three steps: 1) Genomic DNA isolated from whole blood obtained using EDTA as anti-coagulant is combined with PCR Mix and Taq polymerase enzyme and is subjected to amplification of target sequences by PCR using a thermal cycler. 2) Amplified DNA is treated with exonuclease enzyme to generate single-stranded target DNA. 3) Single-stranded, amplified target DNA is mixed with hybridization and genotyping reagents and transferred to an eSensor® Test cartidge, and the cartridge is inserted in the eSensor® XT-8 Instrument. The instrument controls the circulation of the cartridge to allow hybridization at a controlled temperature and then detects and genotypes the sample by voltammetry.
Genotyping of the test panel polymorphisms is achieved by a sandwich assay principle: 1) Each pair of electrodes contains a different synthetic oligonucleotide capture probe which is complementary to one of the target DNA fragments. 2) The hybridization reagents contain pairs of ferrocene-labeled synthetic oligonucleotide signal probes; one member of each pair is complementary to the major allele sequence of the target polymorphism, while the second member of the pair is complementary to the minor allele sequence. Each member of the probe pair has a ferrocene label with a different oxidation potential for each allele. 3) Single-stranded, amplified target DNA hybridizes to its specific capture probe, and in turn hybridizes to the allele-specific, ferrocene-labeled signal probe. 4) Each electrode of the array is analyzed by voltammetry; the target polymorphism is determined by the location of the electrode containing the capture probe, and the genotype is identified by the ratio of signals from the allele-specific ferrocene labels. The array also includes positive controls to confirm the hybridization reaction and detect non-specific signals.
Upon completion of the test, the EEPROM chip on the cartridge contains information that prevents its re-use with a new sample. The eSensor® XT-8 instrument analyzes the results and provides a report of the test results.
Here's a summary of the acceptance criteria and study details for the eSensor® Thrombophila Risk Test, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The 510(k) summary does not explicitly state "acceptance criteria" with numerical thresholds prior to presenting the results. However, the performance characteristics, particularly the "Method Comparison" results, implicitly serve as the primary demonstration of meeting performance expectations against a gold standard. For the reproducibility studies, "100% agreement" strongly implies this as an implicit acceptance criterion for internal consistency.
| Performance Characteristic | Implicit Acceptance Criteria (Derived from results) | Reported Device Performance |
|---|---|---|
| Method Comparison (Agreement with DNA Sequencing) | ||
| FV Mutation (WT) | 100% Agreement (or very high agreement >97%) | 100.00% (Final results) |
| FV Mutation (HET) | 100% Agreement (or very high agreement >97%) | 100.00% (Final results) |
| FV Mutation (MUT) | 100% Agreement (or very high agreement >70%) | 100.00% (Final results) |
| FII Mutation (WT) | 100% Agreement (or very high agreement >97%) | 100.00% (Final results) |
| FII Mutation (HET) | 100% Agreement (or very high agreement >89%) | 100.00% (Final results) |
| FII Mutation (MUT) | 100% Agreement (or very high agreement >68%) | 100.00% (Final results) |
| MTHFR (C677T) Mutation (WT) | 100% Agreement (or very high agreement >95%) | 100.00% (Final results) |
| MTHFR (C677T) Mutation (HET) | 100% Agreement (or very high agreement >97%) | 100.00% (Final results) |
| MTHFR (C677T) Mutation (MUT) | 100% Agreement (or very high agreement >90%) | 100.00% (Final results) |
| MTHFR (A1298C) Mutation (WT) | 100% Agreement (or very high agreement >95%) | 100.00% (Final results) |
| MTHFR (A1298C) Mutation (HET) | 100% Agreement (or very high agreement >97%) | 100.00% (Final results) |
| MTHFR (A1298C) Mutation (MUT) | 100% Agreement (or very high agreement >90%) | 100.00% (Final results) |
| Reproducibility (Inter-laboratory, Inter-operator) | 100% Agreement (First Pass Correct Calls and Final Correct Calls) | "All samples gave 100% correct calls." |
| Genomic DNA Extraction Reproducibility | 100% Agreement (Correct Calls) | "All samples gave 100% correct calls when compared with DNA sequencing." |
| Lot to Lot Reproducibility | 100% Agreement (Correct Calls) | "All samples gave 100% correct calls when compared with DNA sequencing." |
| Limit of Detection | 100% Agreement at 10-500ng; High agreement at 1ng (e.g., >95%) | 100% agreement at 10-500ng; 98% agreement at 1ng. |
Note on "Implicit Acceptance Criteria": The document consistently reports 100% (final) agreement with DNA sequencing across all categories in the Method Comparison and 100% correct calls for reproducibility studies. This suggests that achieving perfect or near-perfect agreement with the gold standard (DNA sequencing) and internal consistency was the unstated "acceptance criterion" for these performance studies. The 95% LCB (Lower Confidence Bound) values provided in the method comparison table suggest that the statistical power was sufficient to be confident in these high agreement rates, even with sometimes smaller sample sizes for specific mutation types.
2. Sample Sizes Used for the Test Set and Data Provenance
- Test Set Sample Size:
- Method Comparison: 219 gDNA samples.
- Reproducibility (Inter-laboratory, Inter-operator): 5 gDNA samples run in duplicate each day by each of 6 operators (2 operators per site across 3 sites) over 5 days = 5 x 2 x 3 x 5 = 150 test runs. The table states "Samples Tested: 50" per operator, totaling 300 tests. This implies a set of 5 gDNA samples were tested multiple times.
- Genomic DNA Extraction Reproducibility: 6 whole blood samples tested with 3 different extraction methods = 18 tests.
- Lot to Lot Reproducibility: 5 genomic DNA samples tested in duplicates using 3 different kit lots = 30 tests.
- Limit of Detection: 2 genomic DNA samples, each tested 20 times at 5 different concentrations = 2 x 20 x 5 = 200 tests.
- Data Provenance: Not explicitly stated (e.g., country of origin). The document mentions "3 different sites and 1 internal site" for the reproducibility study, indicating multi-site testing within an unspecified geographic region. The "Method Comparison" study uses "gDNA samples extracted from whole blood," but the origin of these samples is not detailed. All data appears to be prospective in the sense of being generated specifically for these performance studies.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Number of Experts: Not applicable in the traditional sense, as the ground truth was established by DNA sequencing, which is a laboratory method, not human expert consensus.
- Qualifications of Experts: Not applicable. DNA sequencing is a technical standard.
4. Adjudication Method for the Test Set
- Adjudication Method: Not applicable. The ground truth (DNA sequencing) is considered the definitive standard. Any discrepancies between the eSensor® test and DNA sequencing would be considered an error by the eSensor® test, not a disagreement among experts requiring adjudication. The document mentions "Final Results" after "additional run for a single no-call" in the Lot to Lot study, suggesting a re-run policy for initial "no-calls" rather than adjudication. Similarly, in the method comparison, "Final Results" reflect cases where initial "no-calls" were resolved, making the "Final Agreement" 100%.
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 molecular diagnostic test for genotyping, not an imaging diagnostic requiring interpretation by human readers. Therefore, the concept of human readers improving with AI assistance does not apply here.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
- Yes, a standalone performance study was done. This entire submission focuses on the performance of the eSensor® system (instrument + assay kits) as a standalone diagnostic device. The results are compared directly against DNA sequencing (the gold standard), and the system provides results without real-time human interpretation for genotype determination. Human intervention is limited to sample preparation, loading, and reviewing the automatically generated report.
7. The Type of Ground Truth Used
- The type of ground truth used was DNA sequencing. This is explicitly stated across various sections, most notably under "Genomic DNA Extraction Reproducibility," "Lot to Lot Reproducibility," and "Method Comparison" where "All samples gave 100% correct calls when compared with DNA sequencing."
8. The Sample Size for the Training Set
- The document does not explicitly state a separate "training set" or its sample size. Diagnostic kits like this, especially those based on hybridization and electrochemical detection principles for known mutations, are typically developed and optimized during an R&D phase, and then validated with the performance studies presented. There isn't typically a distinct "training set" in the same way machine learning algorithms have. The pre-market submission focuses on the validation of the finalized device.
9. How the Ground Truth for the Training Set Was Established
- Since a separate "training set" is not explicitly mentioned or detailed, the method for establishing ground truth for such a set is also not described. If an internal training or optimization phase utilized samples, it can be inferred that DNA sequencing would have been the likely method for establishing their ground truth, consistent with the validation studies.
§ 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.)