(81 days)
OPUS D-Dimer is an in vitro fluorogenic enzyme immunoassay (ELISA) for the quantitative measurement of cross-linked fibrin degradation products (XL-FDP) containing D-Dimer in human plasma, used in the diagnosis of thromboembolic events. OPUS D-Dimer is intended for use with the OPUS analyzers.
OPUS D-Dimer is a set of reagents intended to be used together with the OPUS immunoassay analyzers for the quantitative measurement of cross-linked fibrin degradation products containing D-Dimer in human plasma.
Here's a breakdown of the acceptance criteria and study information for the Behring Diagnostics Inc. OPUS® D-Dimer device, based on the provided text:
Acceptance Criteria and Device Performance
The document does not explicitly state pre-defined "acceptance criteria" in the format of pass/fail thresholds for the device's performance. Instead, it presents performance characteristics determined through several studies. The underlying acceptance is implied by the FDA's "substantial equivalence" determination, meaning the performance is considered comparable and safe/effective relative to the predicate device.
However, we can infer the reported device performance from the "Device Performance Characteristics" section.
Table of Performance Characteristics:
The document doesn't provide a typical "acceptance criteria" table with specific targets. Instead, it reports the resulting performance metrics from the studies conducted.
| Performance Metric | Reported Device Performance (OPUS D-Dimer) |
|---|---|
| Precision | |
| Intra-assay %CV | 7.3% to 8.9% (at two control levels) |
| Inter-assay %CV | 8.6% to 10.3% (at two control levels) |
| Accuracy | |
| Recovery (pooled human serum spiked) | 85% to 95% (across five D-Dimer levels) |
| Correlation with predicate device (ASSERACHROM D-Di) | Correlation Coefficient: 0.93 |
| Y-intercept: 0.34 | |
| Slope: 0.89 |
Study Details
2. Sample Size Used for the Test Set and Data Provenance
- Accuracy by Correlation: 321 human plasma samples.
- Data Provenance: The document does not explicitly state the country of origin for the data or whether the samples were collected retrospectively or prospectively. It refers to "human plasma samples."
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. For in vitro diagnostic devices like D-Dimer assays, "ground truth" is typically established by comparing the device's results to a recognized reference method or a legally marketed predicate device. The document uses the "ASSERACHROM® D-Di" as the comparator for accuracy by correlation, implying its results served as the reference. There's no mention of human experts establishing ground truth for the D-Dimer levels in the plasma samples.
4. Adjudication Method for the Test Set
- This information is not applicable/provided. The evaluation methods described (precision studies, recovery studies, and correlation with a predicate device) do not involve adjudication by multiple human readers in the way typically seen for medical imaging or clinical decision support AI devices. The comparison is between the new device and a reference method.
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, an MRMC comparative effectiveness study was not performed. This type of study is relevant for AI-powered diagnostic aids that assist human interpretation (e.g., radiologists reading images). The OPUS D-Dimer is a standalone in vitro diagnostic assay that quantitatively measures a biomarker, not a device that assists human readers in interpreting clinical cases.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Yes, the OPUS D-Dimer is an in vitro diagnostic standalone device. Its performance characteristics (precision, recovery, and correlation with another assay) are reported for the device itself, without human-in-the-loop interpretation being part of the primary performance evaluation. It's an automated fluorometric immunoassay system.
7. The Type of Ground Truth Used
- For the "Accuracy by Correlation" study, the ground truth was effectively the results obtained from the legally marketed predicate device, ASSERACHROM® D-Di, which is a "commercially available D-Dimer assay." For precision and recovery studies, the ground truth was based on pre-defined control materials or spiked samples with known concentrations.
8. The Sample Size for the Training Set
- This document does not mention a "training set" in the context of machine learning or AI models. The OPUS D-Dimer is an immunoassay system. While the system would have undergone internal development, calibration, and validation, the concept of a separate "training set" and "test set" for an AI algorithm is not applicable here. The reported studies describe analytical performance evaluation, not AI model deployment.
9. How the Ground Truth for the Training Set was Established
- As mentioned above, the concept of a "training set" for an AI model is not applicable to this device. For the development and calibration of the immunoassay, ground truth would have been established through highly characterized reference materials and established laboratory methods. The document does not provide details on the specific methods used for establishing these intrinsic reference values during product development.
§ 864.7320 Fibrinogen/fibrin degradation products assay.
(a)
Identification. A fibrinogen/fibrin degradation products assay is a device used to detect and measure fibrinogen degradation products and fibrin degradation products (protein fragments produced by the enzymatic action of plasmin on fibrinogen and fibrin) as an aid in detecting the presence and degree of intravascular coagulation and fibrinolysis (the dissolution of the fibrin in a blood clot) and in monitoring therapy for disseminated intravascular coagulation (nonlocalized clotting in the blood vessels).(b)
Classification. Class II (performance standards).