(208 days)
The VeraCode Genotyping Test for Factor V and Factor II is an in vitro diagnostic device for the detection and genotyping of Factor V Leiden G1691A and Factor II (Prothrombin) G20210A point mutations in DNA obtained from EDTA-anticoagulated human blood samples. The test is intended for use on the BeadXpress System. The VeraCode Genotyping Test for Factor V and Factor II on the BeadXpress System is indicated for use as an aid to diagnosis in the evaluation of patients with suspected thrombophilia.
The VeraCode Genotyping Test for Factor V and Factor II assay consists of reagents sufficient for 96 tests, consisting of two boxes containing pre-PCR and post-PCR reagents. The pre-PCR box contains the following reagents: MTR1 (1 x 1.2 mL). AB1 (1 x 4 mL), AOP1 (1 x 4.8 mL), ELM (1 x 4.8 mL), FSB (1 x 4.8mL), UB3 buffer (2 x 4.8 mL) and AE1 reagent (2 x 4.8 mL). The post-PCR box contains MSS reagent (1 x 4.8 mL) and Fast Start Taq DNA Polymerase (1 x 60 µL), VW2 buffer (1 x 60 mL), a VeraCode FV/FII Bead Plate with holographically inscribed glass microbeads aliquoted in strip-well plates, a test-specific kit manifest file and sample sheet files (containing test specific outcome specifications and sample plate layout files used to interpret and report genotype results). A magnet plate is also required but sold separately.
Here's a breakdown of the acceptance criteria and the study details for the Illumina VeraCode® Genotyping Test for Factor V and Factor II, based on the provided 510(k) summary:
1. Table of Acceptance Criteria and Reported Device Performance
The device's performance is primarily evaluated through reproducibility (precision) and accuracy (method comparison).
Acceptance Criteria for Reproducibility (Precision):
While explicit numerical acceptance criteria for reproducibility are not stated as "acceptance criteria," the study aimed to demonstrate high agreement for correct calls across different operators, sites, and days. The results presented in the summary show very high percentage agreements and 95% lower confidence bounds (LCB) nearing 100% after retesting, indicating that the implicit acceptance criterion was near-perfect agreement for calling genotypes correctly.
| Test Parameter | Acceptance Criteria (Implicit) | Reported Device Performance (After Retest) |
|---|---|---|
| Reproducibility | High percentage agreement (>95%) and 95% LCB for correct genotype calls across sites, operators, and days. | Factor V: Wild Type: 100% agreement (99.38% LCB); Heterozygous: 99.58% agreement (98.04% LCB); Homozygous: 100% agreement (98.35% LCB). All initially "no calls" (failures) were resolved upon re-test. |
Factor II: Wild Type: 100% agreement (99.45% LCB); Heterozygous: 100% agreement (98.35% LCB); Homozygous: 100% agreement (98.35% LCB). All initially "no calls" (failures) were resolved upon re-test. | ||
| Accuracy | High overall percent agreement (>95%) and 95% LCB compared to bi-directional DNA sequencing for genotype calls. | Factor V: Wild Type: 100% agreement (98.6% LCB); Heterozygous: 100% agreement (94.07% LCB); Homozygous: 92.86% agreement (70.33% LCB) with one of the 14 samples still being a "no call" after repeat testing. |
Factor II: Wild Type: 99.59% agreement (98.08% LCB); Heterozygous: 100% agreement (88.27% LCB); Homozygous: 100% agreement (65.18% LCB). |
Note: The 95% LCB for homozygous Factor V (70.33%) and Factor II (65.18%) in the accuracy study, while lower than other categories, likely reflect the smaller sample size for these less common genotypes.
2. Sample Size and Data Provenance for the Test Set
- Test Set Sample Size:
- Reproducibility (Precision) Study: A panel of 15 genomic DNA samples (3 for each of the 5 possible genotypes including Wild Type). Each sample was tested in duplicate once a day for 5 non-consecutive days at each of three sites by two operators. This results in a significant number of replicates (e.g., for Factor V Wild Type, 3 samples * 2 replicates * 5 days * 3 sites * 2 operators = 180 total instances, with slight variations in the tables indicating initial no-calls).
- Accuracy (Method Comparison) Study: 92 patient samples were accrued at each of the three sites, yielding a total of 276 patient samples. Additionally, each site received two archived DNA samples as positive controls.
- Data Provenance: The report does not explicitly state the country of origin. However, the samples for the accuracy study were "prospectively drawn blood samples" (for interference testing) and "pre-selected or unscreened patients undergoing Factor V testing" (for method comparison), suggesting a combination of prospective and retrospective (archived) samples for the accuracy study. For reproducibility, it uses "genomic DNA samples isolated from blood" and "commercially available cultured cells."
3. Number of Experts and Qualifications for Ground Truth
- Number of Experts: For the accuracy study (method comparison), the ground truth was established by "bi-directional DNA sequencing analysis performed at an independent reference laboratory." The number of individuals/experts involved in this independent sequencing and interpretation is not specified, nor are their specific qualifications (e.g., number of years of experience). However, "bi-directional DNA sequencing" is a well-established and highly accurate method for genotyping, implying expert-level analysis.
4. Adjudication Method for the Test Set
- There appears to be no explicit adjudication method described for resolving discrepancies between the device's results and the ground truth (bi-directional sequencing). The summary reports the raw agreement.
- For the device's own internal "no calls" (samples generating an invalid result), the "no calls" were retested once. This retesting resolved most, but not all, initial "no calls," as seen in the tables (e.g., one FVL Homozygous sample in the accuracy study remained a "no call" after retesting).
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No MRMC comparative effectiveness study was done. This device is an in vitro diagnostic (IVD) genetic test, which typically has a standalone performance assessment against a gold standard (like sequencing) rather than evaluating human reader performance with or without AI assistance.
6. Standalone Performance Study (Algorithm Only)
- Yes, a standalone performance study was done. The entire analytical performance section (Precision/Reproducibility and Method Comparison) describes the performance of the device (VeraCode Genotyping Test for Factor V and Factor II on the BeadXpress System, with VeraScan software) as a standalone system. The results of the device were directly compared against the established ground truth (bi-directional sequencing), without human intervention in the interpretation process of the device's output. The software interprets and reports the genotype.
7. Type of Ground Truth Used
- The primary ground truth used for both the reproducibility and accuracy studies was bi-directional DNA sequencing. This is considered a highly reliable and definitive method for determining gene mutations.
8. Sample Size for the Training Set
- The document does not provide information on the sample size used for the training set. As a 510(k) submission for a diagnostic test kit based on established molecular biology principles (PCR, allele-specific primer extension, hybridization), the development of the "algorithm" (the VeraScan software and kit manifest file) would typically rely on well-characterized samples and biochemical parameters rather than a large machine learning training set in the modern sense. The "assay-specific kit manifest file" contains the parameters and cutoffs used to interpret and report genotype results, implying these were established during development.
9. How the Ground Truth for the Training Set Was Established
- Similar to the training set sample size, the document does not explicitly detail how ground truth for the training set (development of the kit manifest and software interpretation rules) was established. It's inferable that the development team used well-characterized reference samples (likely with known genotypes confirmed by sequencing or other gold-standard methods) to define the assay parameters, thresholds, and interpretation rules encoded in the kit manifest file that guides the VeraScan software. The "Preliminary passing criteria where all replicates of all genotypes produce the correct result when compared to bi-directional sequencing" mentioned in the detection limit section suggests an iterative process referencing sequencing during development.
§ 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.)