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For the in vitro quantitative measurement of Troponin I (cTnI) in human heparin plasma to aid in the diagnosis of myocardial infarction.

For use in the calibration of the Vitros Immunodiagnostic System for the quantitative measurement of cardiac Troponin I (cTnI) in human heparin plasma.

The Vitros Troponin I assay is performed using the Vitros Troponin I Reagent Pack and Vitros Immunodiagnostic Products Troponin I Calibrators on the Vitros ECi Immunodiagnostic System with Intellicheck ™ . An immunometric technique is used. Cardiac Troponin I present in the sample reacts simultaneously with a biotinylated antibody (mouse monoclonal anti-cTnI) and a horseradish peroxidase (HRP)-labeled antibody conjugate (affinity purified goat polyclonal anti-cTnI). The antigen-antibody complex is captured by streptavidin on the wells. Unbound materials are removed by washing. A reagent containing luminogenic substrates (a luminol derivative and a peracid salt) and an electron transfer agent (a substituted acetanilide) is added to the wells. The HRP in the bound conjugate catalyzes the oxidation of the luminol derivative, producing light. The electron transfer agent increases the level and duration of the light produced. The light signals are read by the Vitros ECi System. The amount of HRP conjugate bound is directly proportional to the concentration of cTnI present in the sample.

This document describes the acceptance criteria and study proving the VITROS Immunodiagnostic Products Troponin I Reagent Pack and Calibrators meet the criteria.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implied by the comparison to the predicate device and the establishment of diagnostic thresholds.

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

• Correlation Data Test Set:

  • Sample Size: 198 samples
  • Data Provenance: "panel of patient samples from a variety of clinical categories." (Retrospective, origin not specified beyond "patient samples")

• Upper Reference Limit (URL) Test Set:

  • Sample Size: 798 fresh heparin plasma samples
  • Data Provenance: "normal blood donors between the ages of 18-89 (61.3% male donors and 38.7% female donors collected across six sites)." (Prospective or retrospective, origin not specified beyond "six sites"; implies multi-center U.S. data likely given FDA submission)

• AMI Cut-off Test Set:

  • Sample Size: 458 chest pain patients, where 78 were diagnosed with AMI.
  • Data Provenance: "chest pain patients" (Retrospective clinical data, origin not specified beyond "patients")

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

The document does not specify the number or qualifications of experts used to establish ground truth for any of the test sets.

• For the correlation data, the ground truth is implicitly the values obtained from the DADE Dimension™ RxL Cardiac Troponin-I (TROP) Method (the predicate device).
• For the upper reference limit, "normal blood donors" classification would likely be based on standard health screenings, not expert consensus on troponin levels.
• For the AMI cut-off, the "diagnosis of AMI" for the 78 patients would be the ground truth. This diagnosis is typically established by clinicians based on a combination of patient symptoms, ECG changes, and cardiac biomarker levels (including troponin, but not exclusively). The specific method or expert involvement in confirming these AMI diagnoses is not detailed.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method for establishing ground truth for any of the test sets. Ground truth for the correlation data is the predicate device's measurement. Ground truth for normal donors is their clinical classification as healthy. Ground truth for AMI patients is their clinical diagnosis, but the process of this diagnosis (e.g., whether it involved multiple blinded reviewers) is not detailed.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance

This section is not applicable. The device is an in vitro diagnostic (IVD) assay measuring a biomarker (Troponin I). It is not an AI-assisted diagnostic imaging device or an algorithmic tool intended to directly assist human readers in interpreting complex visual or clinical data in the way an MRMC study would typically evaluate. The assay directly provides a quantitative result.

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

This section is applicable, and the studies outlined are standalone performance evaluations of the device. The device itself (the VITROS Troponin I assay) is an automated system that provides a quantitative measurement. The reported performance metrics (correlation coefficient, URL, AMI cut-off with sensitivity/specificity) are derived from the device's output without human intervention in the measurement process after sample introduction. The human "in-the-loop" would be the clinician interpreting the result, but the performance data presented is the "algorithm only" (assay only) output.

7. The Type of Ground Truth Used

• Correlation Data: The ground truth was the measurements obtained from the predicate device (DADE Dimension™ RxL Cardiac Troponin-I (TROP) Method).
• Upper Reference Limit: The ground truth was the clinical classification of "normal blood donors."
• AMI Cut-off: The ground truth was the clinical diagnosis of "AMI" for 78 patients out of a total of 458 chest pain patients. This represents a form of outcomes data or clinical diagnosis.

8. The Sample Size for the Training Set

The document does not explicitly mention a separate "training set" in the context of machine learning. For IVD devices, method validation studies typically involve defining parameters (like the URL and cut-off points) based on observed performance in clinical populations rather than explicit "training" in the AI sense.

• The upper reference limit (0.08 ng/mL) was established using a panel of 798 fresh heparin plasma samples from normal blood donors. This can be considered the "dataset used to define a normal range."
• The AMI cut-off (0.4 ng/ml) was determined using 458 chest pain patients (78 with AMI) via Receiver Operator Characteristic (ROC) curve analysis. This can be considered the "dataset used to optimize a diagnostic threshold."

These datasets serve a similar purpose to a training set in that they are used to establish and optimize operating parameters for the device's interpretation.

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

• For the Upper Reference Limit: The ground truth for the 798 samples was their status as "normal blood donors" (presumably healthy individuals without cardiac disease) aged 18-89. This classification would typically be based on standard donor screening procedures and health questionnaires.
• For the AMI Cut-off: The ground truth for the 458 chest pain patients was their clinical diagnosis, specifically whether they were "diagnosed with AMI." This diagnosis would have been made by medical professionals based on clinical presentation, ECG findings, and other relevant diagnostic information available at the time of the patient's care.

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