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The DIMERTEST® Latex Assay is intended for the rapid qualitative or semi-quantitative evaluation of circulating derivatives of cross-linked fibrin degradation products (D-dimer) in human plasma.

The DIMERTEST® Latex Kit is a qualitative and semi-quantitative latex agglutination slide test for cross-linked fibrin degradation products in human plasma. The active ingredient in the DIMERTEST® product is the latex reagent. This reagent consists of highly specific D-dimer monoclonal antibodies attached to polystyrene latex particles. When mixed with the latex reagent, the presence of antigen (Ddimer) in a plasma sample results in agglutination of the latex particles which can be seen with the unaided eye. A semi-quantitative estimate of the Ddimer concentration can be made by preparing dilutions of a plasma sample. The concentration is determined according to a titration matrix.

Plasma from normal individuals is not expected to agglutinate DIMERTEST® Latex. Reactive fibrinolysis will be demonstrated by latex agglutination at a plasma concentration of approximately 200 ng/mL D-dimer.

Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:

DIMERTEST® Device Acceptance Criteria and Performance Study

The DIMERTEST® Latex Assay is intended for the rapid qualitative or semi-quantitative evaluation of circulating derivatives of cross-linked fibrin degradation products (D-dimer) in human plasma. The submission K974596 concerns a modified version of the DIMERTEST® product, where American Diagnostica Inc. (ADI) took over manufacturing from AGEN Biomedical Ltd. and made some changes, including a change in the latex supplier and a refined cut-off value.

1. Table of Acceptance Criteria and Reported Device Performance

The provided document doesn't explicitly state "acceptance criteria" with numerical targets in the conventional sense for a new device. Instead, it focuses on demonstrating substantial equivalence to an existing predicate device (DIMERTEST® K882944) by comparing performance characteristics. The implied acceptance criteria are that the modified device's performance (specificity, sensitivity, and analytical characteristics) is comparable to or improved from the predicate device and that the new cut-off is adequately validated.

2. Sample Sizes and Data Provenance for Test Set

• Specificity Comparison:
  • Sample Size: 170 Blood Bank donor plasma samples.
  • Data Provenance: In-house comparative study, ostensibly healthy volunteers. The country of origin is not specified but implied to be North America given the submitter's location (Stamford, CT). Retrospective.
• Sensitivity Comparison:
  • Sample Size: 145 plasmas from hospital patients.
  • Data Provenance: In-house comparative study, patients with a high probability of thrombotic conditions. Country of origin not specified, implied North America. Retrospective.
• Clinical Cut-off Validation:
  • Sample Size: 373 patient plasmas.
  • Data Provenance: Not explicitly stated, but these were "patient plasmas." Country of origin not specified, implied North America. Contemporaneous testing with an FDA-cleared EIA method suggests a prospective element to this validation step.

3. Number of Experts and Qualifications for Ground Truth

The document does not specify the use of experts to establish ground truth for the test set. For the normal donor samples, "ostensibly healthy volunteers" serve as the implicit negative ground truth. For the "hospital patients who had a high probability of thrombotic conditions," the "high probability" suggests clinical assessment as the ground truth, but specific details about how this was determined or by whom are not provided.

4. Adjudication Method for Test Set

The document does not describe any adjudication method for the test set. The results are presented as direct comparisons between the modified device and either the predicate device or a separate FDA-cleared EIA method.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was done. This device is a biochemical assay (latex agglutination test), not an imaging or diagnostic device that typically involves human readers interpreting results in a complex way that requires AI assistance. The interpretation (agglutination or not) is largely qualitative or semi-quantitative based on visual inspection.

6. Standalone Performance (Algorithm Only)

This device is a standalone diagnostic kit (a latex agglutination assay) that produces a direct result. It does not involve an "algorithm" in the computational sense nor human-in-the-loop performance with an AI system. The performance characteristics described (precision, linearity, analytical specificity, cut-off validation, and method comparison) represent its standalone performance.

7. Type of Ground Truth Used

• Specificity Study: Implicitly, "normal individuals" from Blood Bank donor plasma samples served as the negative ground truth.
• Sensitivity Study: Implicitly, "hospital patients who had a high probability of thrombotic conditions" served as the positive ground truth.
• Cut-off Validation: The FDA cleared Dimertest Gold EIA method (K945642) served as a comparative reference for determining and validating the new cut-off. This could be considered a reference method ground truth.

8. Sample Size for the Training Set

The document does not explicitly mention a separate "training set" for the device's development or performance evaluation in the context of machine learning. The studies described are performance validation studies for the modified device. The 145 patient samples were used to calculate the new clinical cut-off and the 373 patient plasmas were used to validate it. These samples effectively functioned as the data used to refine and confirm a key aspect of the device's operation.

9. How Ground Truth for the Training Set Was Established

As there's no explicit "training set" in the machine learning sense, the ground truth for the data used to establish or validate the cut-off was as follows:

• For the 145 patient plasmas used to calculate the new cut-off, the comparison was made against the D-dimer values determined by the predicate DIMERTEST® reagent.
• For the 373 patient plasmas used to validate the new cut-off, the comparison was made against the results from the FDA cleared Dimertest Gold EIA method (K945642).

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The Dimertest Latex Assay is intended for the rapid qualitative or semi-quantitative evaluation of circulating derivatives of cross-linked fibrin in human plasma.

Not Found

The provided text describes a 510(k) clearance for the Dimertest Latex Assay but does not contain any information regarding specific acceptance criteria, study details, or performance metrics.

Therefore, I cannot provide the requested table or answer the specific questions about the study design, sample sizes, ground truth establishment, or expert involvement. The document primarily focuses on the regulatory clearance of the device as substantially equivalent to a predicate device.

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