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BGM Galectin-3 is an in vitro diagnostic device that quantitatively measures galectin-3 in serum or EDTA-plasma by enzyme-linked immunosorbant assay (ELISA) on a microtiter plate platform to be used in conjunction with clinical evaluation as an aid in assessing prognosis of patients diagnosed with chronic heart failure (HF). BGM Galectin-3 is indicated for prescription use only.

BGM Galectin-3 is a microtiter plate-based sandwich enzyme-linked immunosorbant assay (ELISA) for the quantitative determination of galectin-3 levels in human serum and plasma. BGM Galectin-3 consists of a rat monoclonal anti-mouse galectin-3 antibody coated microtiter plate serving as the solid phase capture antibody and a horseradish peroxidase (HRP)-labeled mouse monoclonal anti-human galectin-3 antibody functioning as the liquid phase tracer antibody for detecting bound galectin-3.

In the testing procedure, galectin-3 in the standard, control, or patient specimen binds to the immobilized capture antibody; after a wash step, bound galectin-3 is detected by the addition of HRP-labeled anti-galectin-3 antibody. Following a second wash step, the presence of bound galectin-3 is demonstrated by an enzymatic blue color development resulting from the addition of tetramethylbenzidene (TMB) solution as the substrate. Color development is stopped by adding sulfuric acid, changing the color to yellow. Color intensity is read at an absorbance of 450 nm using a colorimetric reader. The absorbance is proportional to the galectin-3 levels in the samples, and test results of the samples are determined using a calibration curve derived from the standards.

BGM Galectin-3 contains the microtiter plate, reagents, assayed quality control materials and standards required to perform analyses on serum or EDTA-plasma samples.

This document describes the analytical and clinical performance of the BGM Galectin-3™ assay.

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" for all tests in a single table, but the "Summary of Performance Data" section describes various tests and their outcomes. For clinical performance, the focus is on hazard ratios and cumulative probabilities.

Here's an integrated table derived from the provided text, using reported outcomes as evidence of meeting implicit acceptance criteria:

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

• Analytical Performance Studies (Precision, Linearity, Matrix Equivalence, Detection Limit, Cross-Reactivity, Interfering Substances): The sample sizes vary per test. For example:
  • Precision: Six (6) EDTA-plasma pools for internal precision, and three (3) EDTA-plasma pools tested at three (3) CLIA labs.
  • Matrix Equivalence: Forty-nine (49) matched serum and EDTA-plasma samples.
  • Detection Limit: Forty-eight (48) replicate measurements for LoB, and four (4) serum samples (each 16 replicates, total 64 measurements) for LoD.
  • Cross-reactivity/Interference: Multiple substances tested, typically at a single concentration, within a small set of samples. The exact number of samples for each interfering substance test is not explicitly stated beyond "purified hemoglobin (up to 500 mg/dL)" or "conjugated bilirubin (up to 16.8 mg/dL)."
• Clinical Validation Study (Test Set):
  • Sample Size: 895 banked EDTA-plasma samples.
  • Data Provenance: From patients in the United States and Canada, representing a controlled multi-center clinical study (HF-ACTION study). This is retrospective data (banked samples).

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

The clinical validation study uses "endpoints" (all-cause mortality, all-cause hospitalization, cardiovascular mortality, heart failure-related hospitalization) which are typically objective, adjudicated events based on patient records. The document does not specify an "expert" panel that retrospectively established a ground truth label for each patient's galectin-3 level outside of the outcomes data. The study validates the assay's ability to predict these objective outcomes.

4. Adjudication Method for the Test Set:

Not applicable in the context of this device. The "ground truth" for the clinical validation is based on objective clinical outcomes (mortality, hospitalization), not expert agreement on an image or diagnosis. The HF-ACTION study itself would have had protocols for determining these outcomes.

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 is an in vitro diagnostic (IVD) assay that measures a biomarker, not an imaging device or AI algorithm requiring human reader interpretation or assistance.

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

The BGM Galectin-3 assay is an entirely standalone device. It quantitatively measures galectin-3 levels from patient samples. There is no human-in-the-loop component for the measurement itself; the clinician interprets the device's numerical output.

7. The Type of Ground Truth Used:

• Analytical Studies: The ground truth is based on reference materials, known concentrations, and established methods for assessing analytical performance (e.g., CLSI guidelines).
• Clinical Validation Study: The ground truth for the clinical validation of the assay's prognostic aid claims is outcomes data, specifically:
  • All-cause mortality
  • All-cause hospitalization
  • Cardiovascular mortality
  • Heart failure-related hospitalization

8. The Sample Size for the Training Set:

The document describes two main groups of samples related to clinical performance:

• Reference Range Determination (healthy population): 1,099 banked plasma samples from apparently healthy subjects. This set was used to establish the expected values for galectin-3 in a normal population.
• Cutoff Value Derivation (HF patients): 582 individuals with HF. This set was used to establish the initial cutoff values for risk stratification (≤ 17.8 ng/mL, 17.8-25.9 ng/mL, > 25.9 ng/mL).

These two sets effectively serve as the "training" or "derivation" sets for the clinical interpretation of the assay.

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

• Reference Range: Established from 1,099 apparently healthy subjects. "Healthy" implies the absence of known heart disease. The exact methods for confirming "healthy" status are not detailed but would typically involve medical history, physical examination, and possibly other diagnostic tests.
• Cutoff Value Derivation: Derived from 582 individuals with HF. The document implies these cutoffs were determined by analyzing the association between galectin-3 levels and adverse outcomes within this derivation cohort. The specific methodology for deriving these cutoffs (e.g., statistical methods like ROC curve analysis or survival analysis) is not explicitly detailed in this summary, but they are subsequently validated in a separate, larger cohort. "HF" diagnosis would be established by clinical criteria, but the specific validation method for that diagnosis is not given.

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