(48 days)
The VFE assay is an in vitro enzyme immunoassay for quantifying the concentration of von Willebrand Factor Antigen in human plasma to aid in differentiating patients with von Willebrand disease from those with Classical Hemophilia A.
VFE is an enzyme immunoassay, in microplate format, intended for the in vitro quantification of von Willebrand Factor antigen in serum or plasma as an aid to differentiate patients with von Willebrand disease from those with classical Hemophilia A. This assay represents an updated technical format, with performance improvements, when compared to the predicate device.
Here's an analysis of the provided text to extract the acceptance criteria and study information:
Device: VFE (von Willebrand Factor Antigen Assay)
1. Table of Acceptance Criteria and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" but rather presents a comparison to a predicate device (SPECTRO vWF) to demonstrate "substantial equivalence." The performance parameters of the VFE are compared to those of the predicate. We can infer that the VFE's performance should be comparable to or better than the predicate's for "substantial equivalence."
| Parameter | Acceptance Criteria (Inferred from Predicate) | Reported Device Performance (VFE) |
|---|---|---|
| Sensitivity | Comparable to 0.23% N | 0.78% N |
| Intra-assay reproducibility - CV | Comparable to 6.2 - 8.0 | 5.0 - 5.8 |
| Inter-assay reproducibility - CV | Comparable to 6.3 - 12.8 | 7.0 - 11.5 |
| Accuracy - R (compared to predicate test results) | N/A (predicate compared to Laurell Rocket) | 0.849 (n=118) |
Note on Sensitivity: The VFE's reported sensitivity (0.78% N) is higher than SPECTRO vWF's (0.23% N). In this context, a higher percentage might indicate a detection limit, where a lower percentage is generally better for sensitivity in an assay (meaning it can detect lower concentrations). However, without further context on the specific units and definition of "% N," it's difficult to definitively say if VFE is "better" or if it represents a different measure. The conclusion statement indicates "similar characteristics," suggesting this difference was not considered a deal-breaker for substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Accuracy (compared to predicate): 118 samples (n = 118)
- Data Provenance: Not explicitly stated. The comparison is made to a predicate test, "SPECTRO vWF," which is also from Ramco Laboratories, Inc. No information regarding the country of origin or whether the data was retrospective or prospective is provided.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
- This information is not provided in the document. The accuracy of the VFE is compared to results from the predicate device, and the predicate's accuracy was "original comparison versus Laurell Rocket electrophoresis results." There is no mention of experts establishing a ground truth.
4. Adjudication Method for the Test Set
- This information is not provided. The comparison is statistical (R value) against a predicate device's results.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance
- No. This device is an in vitro diagnostic (IVD) enzyme immunoassay, not an AI-powered diagnostic imaging device. Therefore, an MRMC study with human readers and AI assistance is not applicable.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Yes, implicitly. The performance data presented (sensitivity, reproducibility, accuracy) represents the standalone performance of the VFE assay itself, without human interpretation in the sense of a "human-in-the-loop" for image or complex data analysis. The assay produces a quantitative result.
7. The Type of Ground Truth Used
- For the VFE's accuracy, the ground truth was the results obtained from the predicate device (SPECTRO vWF).
- For the predicate device's original accuracy, the ground truth was derived from Laurell Rocket electrophoresis results.
8. The Sample Size for the Training Set
- This information is not applicable/not provided. The VFE is an enzyme immunoassay, not a machine learning model that requires a "training set" in the conventional sense. The "training" of an assay involves optimization during development, but specific sample sizes for such an activity are not documented in the same way as for AI models.
9. How the Ground Truth for the Training Set Was Established
- Not applicable/not provided. As mentioned above, this is an immunoassay, not an AI model.
§ 864.7290 Factor deficiency test.
(a)
Identification. A factor deficiency test is a device used to diagnose specific coagulation defects, to monitor certain types of therapy, to detect coagulation inhibitors, and to detect a carrier state (a person carrying both a recessive gene for a coagulation factor deficiency such as hemophilia and the corresponding normal gene).(b)
Classification. Class II (performance standards).