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PATHFAST® hs-cTnl-II is an in vitro diagnostic test for the quantitative measurement of cardiac Troponin I (cTnl) in heparinized or EDTA whole blood and plasma. Measurements of cardiac Troponin I are used as an aid in the diagnosis of acute myocardial infarction (AMI). PATHFAST® hs-cTnI-II is for use in clinical laboratory or point of care (POC) settings.

The PATHFAST® hs-cTnI-II test is a chemiluminescent enzyme immunoassay performed on the PATHFAST® instrument. Patient samples, whole blood or plasma, are dispensed by the operator into the designated area on the reagent cartridge. The instrument combines the patient sample, the antibody coated magnetic particles, and the alkaline phosphatase conjugate and incubates the mixture for 5 minutes at 37℃. During this incubation, the analyte in the patient sample binds to the antibody on the coated particles, and the alkaline phosphatase conjugate binds to the analyteantibody coated-particle. After the incubation, the instrument performs Bound/Free (B/F) separation using Magtration® technology to remove any excess unbound reagents. The chemiluminescent substrate is then added. The substrate is catalyzed by the bound alkaline phosphatase, which results in emission of photons. The photo-multiplier tube in the PATHFAST® instrument detects the photons that are emitted during the reaction. The chemiluminescent count is converted to analyte concentration values by the instrument based on the master calibration curve for the reagent lot. The PATHFAST® hs-cTnI-II test is supplied in reagent kits. Each kit contains sufficient materials for 60 determinations. The calibrator materials are included with the reagent kit and are also available separately. Calibration kits and diluent kits are also provided separately.

The provided text describes the regulatory clearance of the PATHFAST® hs-cTnI-II device, a diagnostic test for cardiac Troponin I (cTnI), and its comparison to a legally marketed predicate device (PATHFAST® cTnI-II, K100130). The focus of this document is on the analytical performance and how modifications to the reporting range do not affect clinical performance, relying on data from the predicate device.

Here's a breakdown of the requested information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

For this device, the "acceptance criteria" are tied to its analytical performance and how it meets the claims for its intended use, especially concerning linearity, detection limits, and maintaining the clinical significance established by the predicate.

2. Sample size used for the test set and the data provenance

The document details analytical studies for linearity and detection limits, but does not describe a specific "test set" for clinical performance in the context of a new study for the PATHFAST® hs-cTnI-II. Instead, it refers to the re-evaluation of data from the predicate device (K100130).

• Linearity/Assay Reportable Range:

  • Sample Size: Unknown specific number of unique whole blood and plasma samples (EDTA and lithium heparin) with low and high values, diluted to produce up to 12 dilution levels per series. Three dilution series of each sample matrix were tested across three different lots of reagents. Each level was tested in replicates of three.
  • Data Provenance: Not explicitly stated (e.g., country of origin, retrospective/prospective). This is an analytical study, not a clinical study on patient outcomes.

• LoB/LoD Studies:

  • Sample Size for LoB: Four plasma samples, replicates of two per sample, repeated twice a day for three consecutive business days, across four lots of reagents. Total 96 determinations (4 lots * 4 samples * 2 replicates * 3 days * 2 times/day, but text says 24 replicates per lot, so 4 lots * 24 = 96).
  • Sample Size for LoD: 4 low samples, twice a day with four lots of reagent over three days. Total 96 replicates.
  • Data Provenance: Not explicitly stated.

• LoQ Study:

  • Sample Size: Two sets of three samples and two reagent lots; each tested in replicates of four, three runs per day. Total 24 replicates per sample per condition. Testing was repeated for each matrix.
  • Data Provenance: Not explicitly stated.

• Clinical Performance (Reference to K100130): The document indicates that the clinical performance evaluation relied on data from the predicate device (K100130). The original reference range study that established the 99th percentile cutoff used numerical results, which were re-evaluated.

  • Sample Size: Not specified for the original predicate study within this document.
  • Data Provenance: Not specified within this document, but pertains to the predicate device's original submission.

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

Not applicable. This document does not describe a new clinical study involving experts to establish a "ground truth" for a test set. The clinical claims (99th percentile cutoff, sensitivity, specificity) rely on the original predicate device's studies, where ground truth would have been established through clinical diagnosis of Acute Myocardial Infarction.

4. Adjudication method for the test set

Not applicable. No new clinical test set with human interpretation and adjudication is described.

5. 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

Not applicable. This device is an in vitro diagnostic test for measuring a biomarker, not an imaging device or algorithm requiring human interpretation or AI assistance in that context.

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

This refers to the analytical performance of the PATHFAST® hs-cTnI-II instrument and reagents. The "standalone" performance is effectively captured by the linearity, LoB, LoD, and LoQ studies, which measure the assay's ability to quantitatively measure cTnI in samples directly, without human interpretation of subjective outputs. The performance described in the table above reflects this standalone analytical performance.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

For the analytical studies described in this document (linearity, LoB, LoD, LoQ), the "ground truth" is established through highly controlled laboratory experiments using known concentrations or dilutions, not clinical outcomes or expert consensus on patient cases.

For the clinical claims (99th percentile, clinical sensitivity/specificity), the document refers back to the predicate device (K100130). In such diagnostic tests for AMI, the ground truth for establishing clinical sensitivity and specificity would typically involve:

• Clinical Diagnosis of AMI: Based on established clinical criteria, often including troponin levels, ECG changes, and clinical symptoms, potentially adjudicated by a panel of cardiologists.
• Outcomes Data: Confirmation of AMI or exclusion of AMI through follow-up data.

The specifics of how this ground truth was established for K100130 are not detailed in this document.

8. The sample size for the training set

Not applicable. This device is a quantitative immunoassay, not an AI/ML device that requires a training set in the typical sense for algorithm development.

9. How the ground truth for the training set was established

Not applicable, as there is no training set for an AI/ML algorithm.

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