(66 days)
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The VIDAS® D-Dimer New (DD2) Assay is an automated quantitative test for use on the VIDAS instrument (K891385) for the immunoenzymatic determination of fibrin degradation products (FbDP) in human plasma using the enzyme-linked fluorescent immunoassay (ELFA) technique. The instrument controls all assay steps and assay temperatures. A pipette tip-like disposable device, the Solid Phase Receptacle (SPR), serves as the solid phase as well as a pipettor for the assay. Reagents for the assay are ready-to-use and pre-dispensed in the sealed DD2 Reagent Strips.
This is a summary of the acceptance criteria and study findings for the VIDAS D-Dimer New Assay.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the observed performance in the clinical study, particularly the 100% Negative Predictive Value (NPV) and high sensitivity, which are critical for an exclusion assay. The study aims to demonstrate that the device is effective in ruling out DVT and PE.
| Metric | Acceptance Criteria (Implied) | Reported Device Performance (Overall) | Reported Device Performance (Low & Intermediate PTP) | Reported Device Performance (High PTP) |
|---|---|---|---|---|
| Sensitivity | High (ideally 100% or very close) | 100% (98.4-100% CI) | 100% (97.7-100% CI) | 100% (94.3-100% CI) |
| Specificity | Good enough to reduce unnecessary imaging while maintaining high sensitivity | 37.7% (34.2-41.3% CI) | 37.6% (34.0-41.2% CI) | 45.5% (16.7-76.6% CI) |
| NPV | High (ideally 100% for exclusion) | 100% (98.7-100% CI) | 100% (98.7-100% CI) | 100% (47.8-100% CI) |
| PPV | Reasonable | 32.4% (28.9-36.1% CI) | 25.8% (22.4-29.5% CI) | 91.3% (82.0-96.7% CI) |
2. Sample Size Used for the Test Set and Data Provenance
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Sample Size:
- Overall: 965 PE suspected patients
- Low and Intermediate Pre-test Probability: 891 patients
- High Pre-test Probability: 74 patients
- Site 1 (Angers University Hospital, France): 284 patients
- Site 2 (Geneva University Hospital, Switzerland): 430 patients
- Site 3 (University Hospital, Lausanne, Switzerland): 251 patients
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Data Provenance: Three-site prospective patient management study conducted in:
- Angers University Hospital, Angers, France
- Geneva University Hospital, Geneva, Switzerland
- University Hospital, Lausanne, Switzerland
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document does not explicitly state the number or qualifications of experts used to establish the ground truth for the test set. However, a "clinical Pre-test Probability Assessment (PTP) model" is mentioned as being used in conjunction with the assay, implying clinical evaluation by medical professionals. For DVT/PE diagnosis, the ground truth typically involves a combination of imaging studies (e.g., CT pulmonary angiography, ventilation-perfusion scan for PE; ultrasound for DVT) and clinical assessment.
4. Adjudication Method for the Test Set
The document does not specify an adjudication method for establishing the ground truth diagnoses of PE for the test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study is mentioned. This study focuses on the standalone performance of the VIDAS D-Dimer assay in conjunction with a PTP model for DVT/PE exclusion, not on comparing human readers with and without AI assistance.
6. Standalone Performance
Yes, a standalone performance study was conducted. The reported metrics (Sensitivity, Specificity, NPV, PPV) are for the VIDAS D-Dimer New Assay itself, in conjunction with a clinical Pre-test Probability Assessment.
7. Type of Ground Truth Used
The ground truth for the presence or absence of DVT/PE is implicitly clinical diagnosis, likely established through standard diagnostic protocols for DVT and PE (e.g., imaging, clinical probability scores, and follow-up). The prevalence of PE is reported, indicating confirmed diagnoses.
8. Sample Size for the Training Set
The document does not provide information on a specific "training set" sample size. The performance data presented is from a clinical validation study (test set). For an immunoassay like this, the device itself is not "trained" in the same way a machine learning algorithm is. Its performance characteristics are determined by its chemical and biological detection mechanism, which would have been developed and validated internally by the manufacturer, but details of that development (e.g., sample sizes for assay development or internal validation) are not included in this 510(k) summary.
9. How the Ground Truth for the Training Set Was Established
As mentioned above, the concept of a separate "training set" with ground truth in the context of an immunoassay is not directly applicable in the same way it is for AI/ML devices. The assay's analytical performance and cutoff values would have been established through laboratory studies during development using known positive and negative samples, but these details are not provided in this regulatory submission.
§ 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).