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The CTNI method is an in vitro diagnostic test for the quantitative measurement of cardiac troponin I in human serum and plasma on the Dimension Vista™ System. Measurements of cardiac troponin I are used to aid in the diagnosis of acute myocardial infarction (AMI) and in the risk stratification of patients with acute coronary syndromes with respect to their relative risk of mortality.

Device Description

The CTNI method is a one-step sandwich chemiluminescent immunoassay based on LOCI™ technology. LOCI™ reagents include two synthetic bead reagents and a biotinylated anti-cardiac troponin I monoclonal antibody fragment. The first bead reagent (Sensibeads) is coated with streptavidin and contains photosensitive dye. The second bead reagent (Chemibeads) is coated with a second anti-cardiac troponin I monoclonal antibody and contains chemiluminescent dye. Sample is incubated with Chemibeads and biotinylated antibody to form a particle/cardiac troponin I/biotinylated antibody sandwich. Sensibeads then are added and bind to the biotin to form bead-aggregated immunocomplexes. Illumination of the complex by light at 680 nm generates singlet oxygen from Sensibeads, which diffuses into the Chemibeads and triggers a chemiluminescent reaction. The resulting chemiluminescent signal is measured at 612 nm and is a direct function of the cardiac troponin I concentration in the sample.

AI/ML Overview

Here's an analysis of the provided text regarding the acceptance criteria and supporting studies for the Dimension Vista™ CTNI Flex® reagent cartridge, structured according to your request:

1. Table of Acceptance Criteria and Reported Device Performance

The submission doesn't explicitly define 'acceptance criteria' in a dedicated section with pass/fail thresholds. Instead, it presents performance characteristics and demonstrates substantial equivalence to a predicate device. The implied acceptance is that the new device's performance is comparable to or improved upon the predicate.

Feature	Predicate Device Performance (Dimension® CTNI)	New Device Performance (Dimension Vista™ CTNI)	Implied Acceptance Criteria (relative to predicate)	Met Criteria?
Intended Use	Quantitative determination of cardiac troponin-I in human serum and heparinized plasma for AMI diagnosis and risk stratification in ACS.	Identical.	Identical intended use.	Yes
Assay Type	Photometric immunoassay	Chemiluminescent immunoassay	New technology is acceptable if other performance is comparable or better.	Yes
Reportable Range	0.04 to 40 ng/mL	0.015 to 40 ng/mL	Equal or wider (especially lower) range.	Yes (improved)
Analytical Sensitivity	0.04 ng/mL	0.015 ng/mL	Equal or better (lower) sensitivity.	Yes (improved)
Functional Sensitivity	Not specified	0.04 ng/mL	Functional sensitivity in line with clinical needs (not directly comparable to predicate's unspecified value, but a specified value is a positive).	Yes
Analytical Specificity (Skeletal muscle troponin-I)	0.04 ng/mL (at 1000 ng/mL)	0.14 ng/mL (at 1000 ng/mL)	Comparable specificity.	Yes
Analytical Specificity (Cardiac troponin-T)	0.34 ng/mL (at 1000 ng/mL)	0.05 ng/mL (at 1000 ng/mL)	Comparable or better specificity.	Yes (improved)
Analytical Specificity (Cardiac troponin-C)	0 ng/mL (at 1000 ng/mL)	0 ng/mL (at 1000 ng/mL)	Identical specificity.	Yes
Hook Effect	No high dose effect up to 1800 ng/mL	No high dose effect up to 1000 ng/mL	No hook effect within a relevant clinical range. (Slightly narrower range than predicate but still clinically acceptable).	Yes
Calibration Interval	Updated for each lot, 5 levels, every 60 days.	Updated for each lot, 6 levels, every 30 days.	Updated for each lot with appropriate frequency and levels. (More frequent calibration and more levels could be seen as an improvement in control).	Yes
Sample Volume	50 µL	20 µL	Equal or smaller sample volume.	Yes (improved)
Method Comparison (Slope)	N/A (Predicate vs. itself)	0.99	Close to 1.0 (indicating good agreement).	Yes
Method Comparison (Intercept)	N/A	-0.10	Close to 0 (indicating good agreement).	Yes
Method Comparison (Correlation Coefficient)	N/A	0.993	High (indicating strong linear correlation).	Yes
Serum vs. Plasma (Slope)	N/A	1.02	Close to 1.0 (indicating good agreement).	Yes
Serum vs. Plasma (Intercept)	N/A	0.031	Close to 0 (indicating good agreement).	Yes
Serum vs. Plasma (Correlation Coefficient)	N/A	0.999	High (indicating strong linear correlation).	Yes
Li Heparin vs. Na Heparin (Slope)	N/A	0.99	Close to 1.0 (indicating good agreement).	Yes
Li Heparin vs. Na Heparin (Intercept)	N/A	-0.05	Close to 0 (indicating good agreement).	Yes
Li Heparin vs. Na Heparin (Correlation Coefficient)	N/A	0.998	High (indicating strong linear correlation).	Yes
Reproducibility (Repeatability %CV)	Not explicitly compared with predicate as a criterion.	Low %CVs (3.8%, 1.25%, 1.05%, 1.0%, 1.7%)	Low %CVs demonstrate good precision. (Acceptance is usually based on pre-defined internal company limits or industry standards for similar assays).	Yes
Reproducibility (Within Lab %CV)	Not explicitly compared with predicate as a criterion.	Low %CVs (7.36%, 3.18%, 2.22%, 3.76%, 1.05%)	Low %CVs demonstrate good precision.	Yes

2. Sample Sizes and Data Provenance

Method Comparison (Test Set for predicate comparison):
- Sample Size: 91 split serum patient samples.
- Data Provenance: Not explicitly stated, but implied to be human patient samples. The country of origin is not mentioned. It is retrospective since existing patient samples were used to compare two methods.
Serum versus Plasma Results:
- Sample Size: 63 matched serum and lithium heparin plasma samples.
- Data Provenance: Not explicitly stated (country of origin), implied to be human patient samples. Retrospective.
Lithium Heparin versus Sodium Heparin Results:
- Sample Size: 50 matched lithium and sodium heparin plasma samples.
- Data Provenance: Not explicitly stated (country of origin), implied to be human patient samples. Retrospective.
Reproducibility (Test Set for precision):
- Sample Size: 4 serum pools and 1 Biorad Cardiac Quality Control, Level 2. The number of runs/replicates per sample is specified: "a single test from two independent cups was analyzed twice per day." The total number of individual measurements is not directly provided but can be inferred from the GLSI document referenced.
- Data Provenance: Not explicitly stated (country of origin). Implied to be in-house laboratory testing. Not directly patient samples for this part, but control materials.

3. Number of Experts and Qualifications for Ground Truth

Not applicable. This submission is for an in vitro diagnostic (IVD) test measuring a biomarker (cardiac troponin I). The "ground truth" for method comparison and precision studies is the measurement itself, typically compared against a reference method (the predicate device in this case) or internal controls with known values. There are no human expert adjudicators involved in establishing ground truth for IVD performance characteristics like analytical sensitivity, range, precision, or method correlation.

4. Adjudication Method for the Test Set

Not applicable. As described above, there's no human adjudication for establishing ground truth in these types of analytical performance studies for IVD devices. The comparison is statistical between the two methods' results.

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

No. This is an IVD device, specifically a lab assay. MRMC studies are typically used for imaging devices or other diagnostic systems where human readers interpret output and their performance (with/without AI assistance) is evaluated. This submission focuses on the analytical performance of the assay itself, not human interpretation of results.

6. Standalone (Algorithm Only) Performance Study

Yes, implicitly. The entire submission describes the "standalone" performance of the Dimension Vista™ CTNI Flex® reagent cartridge system. This device is an automated immunoassay, meaning the algorithm/system produces a quantitative result without direct human intervention in the measurement process itself. The data presented reflects the performance of the algorithm and instrumentation together. It's a "device only" performance inherent in IVD submissions.

7. Type of Ground Truth Used

For Method Comparison Studies: The ground truth for the comparison was established by the predicate device (Dade Behring Dimension® CTNI method). The study aims to show good agreement between the new device's results and the predicate's results when testing the same patient samples.
For Reproducibility Studies: The ground truth for reproducibility is the mean concentration of the control materials/patient pools, established through repeated measurements. The goal is to demonstrate consistency and precision around this mean.
For Specificity Studies: The ground truth is the known concentration of interfering substances (skeletal muscle troponin-I, cardiac troponin-T, cardiac troponin-C) in spiked samples, to see if they cross-react with the assay.

8. Sample Size for the Training Set

Training Set Sample Size: Not specified in the provided text. IVD submissions typically focus on validation studies (test sets) rather than detailing the internal development/training an assay might undergo. For an immunoassay, "training" might refer to assay development, optimization of reagents, and initial performance characterization, rather than a distinct "training set" in the machine learning sense.

9. How Ground Truth for the Training Set Was Established

Not explicitly stated/applicable in the same way as AI/ML. For an IVD immunoassay, the "ground truth" during development involves using reference materials, characterized samples, and known concentrations of analytes and interferents to optimize the assay's chemical and enzymatic reactions, antibody binding, and signal detection to accurately measure the target analyte (cardiac troponin I). This iterative process involves internal laboratory testing and characterization rather than an external "ground truth establishment" phase for a discrete "training set."

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