(225 days)
For the in vitro quantitative determination of fibrin degradation products including D-Dimer and X-oligomers. In conjunction with a non-high clinical probability assessment, a normal (
The Tina-Quant® D-Dimer test system is an immunoturbidimetric assay for the in vitro quantitative determination of fibrin degradation products including D-Dimer and X-oligomers. Latex particles of uniform size are coated with monoclonal antibodies (F(ab')2 fragments) to the D-Dimer epitope. The antigen/antibody complexes produced by the addition of samples containing D-dimer lead to an increase in the turbidity of the test reactants, which can be determined turbidimetrically. The calibrator is D-Dimer calibrator and the recommended control material is D-dimer Control I/II.
Here's an analysis of the provided text regarding the Tina-Quant D-Dimer Test System, focusing on acceptance criteria and supporting studies:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Set by the study) | Reported Device Performance (Tina-Quant D-Dimer) | Device Meets Criteria? |
|---|---|---|
| DVT Exclusion | ||
| Sensitivity ≥ X% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 99.3% | Yes (based on stated high sensitivity) |
| Negative Predictive Value (NPV) ≥ Y% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 99.4% | Yes (based on stated high sensitivity) |
| Failure Rate ≤ Z% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 0.6% | Yes (based on stated high sensitivity) |
| PE Exclusion | ||
| Sensitivity ≥ A% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 100% | Yes (based on stated high sensitivity) |
| Negative Predictive Value (NPV) ≥ B% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 100% | Yes (based on stated high sensitivity) |
| Failure Rate ≤ C% (not explicitly stated as an AC in the text, but inferred from high sensitivity claim) | 0% | Yes (based on stated high sensitivity) |
Important Note: The provided text describes the results of the studies but does not explicitly state predefined acceptance criteria (e.g., "The device must achieve a sensitivity of at least 95%"). The phrase "excludes deep vein thrombosis (DVT) and pulmonary embolism (PE) with high sensitivity" implies that the reported values (99.3%, 99.4%, 0.6% for DVT and 100%, 100%, 0% for PE) met the internal criteria for "high sensitivity."
2. Sample Size Used for the Test Set and Data Provenance
- DVT Exclusion Study:
- Sample Size: 812 outpatients with suspected DVT.
- Data Provenance: Multicenter management study. The country of origin is not specified but is likely within regions where such clinical studies are conducted (e.g., North America, Europe) given the 510(k) submission to the FDA. The study is prospective in nature as patients were followed up for 3 months for development of DVT.
- PE Exclusion Study:
- Sample Size: 168 outpatients with suspected PE.
- Data Provenance: Management study. The country of origin is not specified. The study is prospective in nature as patients were followed up for 3 months for development of PE.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
The text does not provide information on the number of experts or their qualifications for establishing the ground truth for the DVT and PE diagnoses. The ground truth (development of DVT or PE) was determined by "further diagnostic testing" (for patients not excluded by D-Dimer and Wells score) and clinical follow-up over 3 months. This typically involves established medical diagnostic procedures and clinical outcomes, implicitly involving medical professionals, but specific details about expert panels are absent.
4. Adjudication Method for the Test Set
The text does not describe an explicit adjudication method (e.g., 2+1, 3+1 for discrepancies) for establishing the ground truth diagnoses of DVT or PE. The studies followed a management strategy:
- Patients with a non-high Wells score and a normal D-Dimer were not subjected to further diagnostic testing but were followed clinically for 3 months.
- Patients who did not meet these exclusion criteria presumably received standard diagnostic workups for DVT/PE which would establish the ground truth.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed. The studies described are management studies evaluating the performance of the Tina-Quant D-Dimer test in conjunction with clinical probability assessment (Wells score) for excluding DVT and PE, rather than comparing human reader performance with and without AI assistance. The device itself is an in vitro diagnostic (IVD) test, not an AI imaging or diagnostic algorithm designed to assist human readers.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, in a sense, the performance metrics reported (sensitivity, NPV, failure rate) reflect the standalone diagnostic utility of the D-Dimer test when used in conjunction with a clinical probability assessment. The "algorithm" here is the combined clinical probability assessment (Wells score) + D-Dimer cutoff. The reported outcomes (e.g., "Only one of 176 such patients developed DVT") are based on the result of this combined diagnostic strategy, where a particular result (non-high PTP + normal D-Dimer) leads to no further testing and a subsequent clinical follow-up. While there's a human in the loop for the Wells score assessment, the test itself has a standalone numerical result.
7. The Type of Ground Truth Used
The ground truth used was outcomes data / clinical diagnosis, specifically:
- For patients who were not excluded by the D-Dimer + Wells score, the ground truth for DVT/PE would likely be established by conventional diagnostic imaging (e.g., ultrasound for DVT, CTPA for PE).
- For the patients who were excluded (non-high PTP + normal D-Dimer), the ground truth was established by absence of clinical events (DVT/PE) during a 3-month follow-up period. The "failure rate" indicates how many of these excluded patients did develop the condition. This indicates that a combination of clinical outcomes and potentially further diagnostic testing was used for the entire study cohort.
8. Sample Size for the Training Set
The text does not provide information on a training set sample size. This is an in vitro diagnostic (IVD) device, which typically undergoes analytical validation (precision, accuracy, measuring range, etc.) and then clinical validation (as described here). The clinical studies presented are for validation/testing, not for training a machine learning model.
9. How the Ground Truth for the Training Set Was Established
As no training set is described for a machine learning context, this question is not applicable based on the provided text. The device is an immunoturbidimetric assay, not an AI/ML diagnostic.
§ 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).