Search Results

MDA® D-Dimer is a homogeneous latex particle based immunoassay for the quantitative determination of crosslinked fibrin degradation products containing the D-dimer domain in citrated human plasma. MDA D-Dimer is an assay for use in conjunction with a clinical Pre-test Probability Assessment (PTP) model in excluding deep vein thrombosis (DVT) in outpatients suspected of a first episode of DVT. MDA D-Dimer can also be used as and in the assessment and evaluation of patients suspected of pulmonary embolism (PE). The assay is designed for use on the MDA automated coagulation analyzers.

bioMerieux Inc. MDA® D-Dimer is a homogeneous latex particle based immunoassay for the quatitative determination of cross-linked fibrin degradation products containing the D-dimer domain in citrated human plasma. These latex particles aggregate in the presence of fibrin derivatives containing the D-dimer domain. The rate of latex microparticle aggregation is proportional to the concentration of D-dimer in the sample. D-dimer concentration may be interpolated from a reference curve.

This summary describes the acceptance criteria and the study proving the MDA® D-Dimer device meets these criteria.

Acceptance Criteria and Device Performance

Study Details for Clinical Performance (DVT Exclusion)

1. Sample Size used for the test set and the data provenance:

   • Sample Size: 556 consecutive eligible outpatients.
   • Data Provenance: Multi-center, prospective cohort study conducted at three hospitals. The country of origin is not explicitly stated but is implied to be the USA given the submission to the FDA by a US-based company.

2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

   • The document does not explicitly state the number or qualifications of experts used to establish the ground truth. It mentions that an MDA D-Dimer test was performed on presentation without knowledge of the Pre-test Probability Assessment (PTP) results. The "ground truth" for DVT diagnosis in patients with a positive D-Dimer and/or high PTP was established through serial compression ultrasound (CUS). For patients with a negative D-Dimer and low/moderate PTP, they underwent no further diagnostic testing but were "followed up for 3 months for development of DVT," which implies clinical outcomes as part of the ground truth.

3. Adjudication method for the test set:

   • The document does not explicitly describe a formal adjudication method (e.g., 2+1, 3+1 consensus) for the diagnosis of DVT. The ground truth appears to be based on a combination of diagnostic imaging (serial CUS for some) and clinical follow-up for outcomes.

4. 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, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (IVD) assay, not an AI-assisted diagnostic imaging tool that would typically involve human readers.

5. If a standalone (i.e. algorithm only without human-in-the loop performance) was done:

   • Yes, the clinical performance described ("The sensitivity, specificity and negative predictive value of the MDA D-Dimer assay for a clinical cut off of 0.50 µg FEU/n1") represents the standalone performance of the assay when used in conjunction with a clinical PTP model. The assay itself (MDA D-Dimer) generates a quantitative output. The clinical "human-in-the-loop" component is the interpretation of that output in the context of the PTP model, but the assay's performance metrics are standalone for its measurement capabilities.

6. The type of ground truth used:

   • The ground truth for DVT diagnosis was a combination of:
     • Diagnostic Imaging: Serial compression ultrasound (CUS) for patients with a positive MDA D-Dimer and/or high Pre-test Probability (PTP).
     • Clinical Outcomes Data: 3-month follow-up for development of DVT in patients with a negative MDA D-Dimer test result and a low or moderate PTP.

7. The sample size for the training set:

   • The document does not specify a training set for algorithm development for the MDA D-Dimer assay. As an immunoassay, its "training" pertains more to establishing its analytical performance parameters (linearity, precision, etc.) and defining a clinical cutoff value. It states that a "clinical cut off value of 0.50 ug FEU/ml previously validated in an accuracy study" was used, suggesting prior studies informed this threshold, but no sample size for that "accuracy study" is provided here.

8. How the ground truth for the training set was established:

   • As noted above, a formal "training set" in the AI/machine learning sense is not applicable here for this immunoassay. However, the clinical cutoff value of 0.50 µg FEU/ml was "previously validated in an accuracy study." The mechanism for establishing ground truth within that prior accuracy study is not detailed in this document.

Ask a specific question about this device

Ask a specific question about this device

MDA® D-Dimer is a homogeneous latex particle based immunoassay (LIA) for the quantitative determination of cross-linked fibrin degradation products containing the D-dimer domain in citrated human plasma. The assay is designed for use on the MDA® 180 automated coagulation analyzer.

D-dimer is elevated in disseminated intravascular coagulation (DIC), deep venous thrombosis (DVT), and pulmonary omboliom and pulmonary embolism.

Organon Teknika's MDA®D-Dimer is a homogeneous latex particle based immunoassay (LIA) for the quantitative determination in human plasma of cross-linked fibrin degradation products containing the D-Dimer domain in human plasma.

D-Dimer containing fibrin degradation products (FbDP) fragments are released when cross-linked fibrin is degraded by plasmin. Cross-linked fibrin is formed when fibrinogen is cleaved by thrombin to form fibrin monomers, which then spontaneously polymerize and are cross-linked by Factor XIIIa. Thrombin is required to cleave fibrinogen as well as to activate Factor XIII. Plasmin-formation is triggered when a fibrin clot is formed. Plasmin degrades some of the cross-linked fibrin and the resulting level of D-Dimer is, therefore, an indirect measure of thrombin generation and subsequent clot formation.

D-Dimer is elevated in disseminated intravascular coagulation (DIC), deep venous thrombosis (DVT), pulmonary embolism. Also, D-Dimer has been reported in the literature to be elevated in other thrombotic conditions.

MDA®D-Dimer is a quantitative homogeneous-phase immunoassay using latex microparticles to photooptically detect binding of specific monoclonal antibody to D-Dimer. These latex particles aggregate only in the presence of fibrin derivatives containing the D-Dimer domain. The rate of latex microparticle aggregation is proportional to the concentration of D-Dimer in the sample. D-Dimer concentration may be interpolated from a reference curve.

Here's a summary of the acceptance criteria and study details for the MDA® D-Dimer device, based on the provided 510(k) submission:

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated as distinct numerical targets in this document. Instead, the study aims to demonstrate "substantial equivalence" to predicate devices, focusing on accuracy (correlation) and precision.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size: For accuracy testing, 175 samples were used ("Reference Method Fibrinostika® FbDP EIA, n=175").
• Data Provenance: Not explicitly stated. The document does not specify the country of origin of the data or whether it was retrospective or prospective.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• This device is an in-vitro diagnostic (IVD) assay. The "ground truth" for the test set is established by comparison to a legally marketed predicate device (Fibrinostika® FbDP EIA). Therefore, no human experts were used to establish ground truth in the way one would for image-based diagnostic AI. The predicate device's results served as the reference.

4. Adjudication Method for the Test Set

• Not applicable as the ground truth was established by another device (predicate device), not through human expert consensus requiring adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size

• No, an MRMC comparative effectiveness study was not done. This is an IVD device, not a diagnostic imaging AI requiring human reader performance evaluation.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

• Yes, a standalone performance evaluation was done. The MDA® D-Dimer device's performance (accuracy, precision, specificity) was evaluated directly against a predicate device and its own internal controls. The results presented are for the device operating independently.

7. The Type of Ground Truth Used

• The ground truth for the accuracy study was established by comparison to a legally marketed predicate device, specifically the Fibrinostika® FbDP EIA. For precision, internal controls with established values were used.

8. The Sample Size for the Training Set

• This document describes the validation of a laboratory assay, not a machine learning algorithm that typically has a distinct training set. Therefore, the concept of a "training set" in the context of AI is not applicable here. The device is an immunoassay, the "training" would be the initial assay development and calibration performed by the manufacturer. No specific "training set" size for an algorithm is provided or relevant.

9. How the Ground Truth for the Training Set Was Established

• Again, since this is a laboratory immunoassay validation and not an AI algorithm, the concept of establishing ground truth for a "training set" is not applicable in the same way. The assay is developed and manufactured to detect specific analytes (D-dimer) with established chemical and biological principles. The "ground truth" during development would rely on known D-dimer concentrations and biological samples to ensure the assay performs as expected.

Ask a specific question about this device