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Access hsTnl is a paramagnetic particle, chemiluminescent immunoassay for the quantitative determination of cardiac troponin I (cTnl) levels in human serum and plasma using the UniCel DxI Access Immunoassay Systems to aid in the diagnosis of myocardial infarction (MI).

Device Description

The Access hsTnl and Access UniCel Dxl 800 Immunoassay System comprise the Access Immunoassay System for the quantitative determination of cardiac troponin I (cTnl) in human serum and plasma. The Access hsTnl reagent packs contain specific reagents for the in vitro diagnostic measurement of cTnl including: R1a: Dynabeads* paramagnetic particles coated with mouse . monoclonal anti-human cTnl antibody suspended in TRIS buffered saline, with surfactant, bovine serum albumin (BSA). < 0.1% sodium azide, and 0.1% ProClin** 300. R1b: 0.1 N NaOH ● R1c: TRIS buffered saline, surfactant, protein (mouse). < 0.1% sodium . azide, and 0.1% ProClin 300. R1d: Sheep monoclonal anti-human cTnl alkaline phosphatase conjugate diluted in ACES buffered saline, with surfactant, BSA matrix, protein (bovine, sheep, mouse), < 0.1% sodium azide, and 0.25% ProClin 300.

AI/ML Overview

The Access hsTnI device is an immunoassay for the quantitative determination of cardiac troponin I (cTnI) levels in human serum and plasma to aid in the diagnosis of myocardial infarction (MI). The study to prove the device meets acceptance criteria involved establishing the 99th percentile Upper Reference Limit (URL) in a healthy population and evaluating clinical performance (diagnostic accuracy) in patients presenting with chest pain or symptoms suggestive of Acute Coronary Syndromes (ACS).

Here's a breakdown of the acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance:

2. Sample Sizes and Data Provenance for Test Set:

99th percentile URL study (healthy adults):
- N (Overall): 1088 (593 females, 495 males).
- Data Provenance: Multicenter prospective study conducted at five geographically diverse locations throughout the United States.
- Demographics: Subjects ranged from 21 to 99 years of age, with 45% being ≥ 60 years of age.
Clinical Performance Study (patients with chest pain/ACS symptoms):
- N (Evaluable subjects): 1,854.
- Data Provenance: Multicenter prospective study conducted at 14 geographically diverse, primary care hospital-associated emergency departments in the United States, reflecting regional, urban, suburban, and rural patient populations.

3. Number of Experts and Qualifications for Ground Truth (Test Set):

Number of Experts: An "independent panel of expert physicians." The exact number is not specified but it is plural, indicating more than one.
Qualifications of Experts: The panel used criteria consistent with the Universal Definition of Myocardial Infarction to adjudicate true MI statuses. This implies they are specialists in cardiology or emergency medicine with expertise in diagnosing MI.

4. Adjudication Method for the Test Set:

Adjudication Method: "Adjudicated by an independent panel of expert physicians using criteria consistent with the Universal Definition of Myocardial Infarction." The adjudicators were blinded to the assay results and the attending physicians' diagnosis. This suggests a consensus-based approach among the expert panel, although the specific voting mechanism (e.g., 2+1, 3+1) is not detailed.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:

No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. The study focused on the performance of the device itself (hsTnI assay) as an aid in diagnosis.

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

Yes, the clinical performance study evaluated the standalone performance of the Access hsTnI assay. The assay results were used to determine sensitivity, specificity, PPV, and NPV relative to the expert-adjudicated MI diagnosis. This represents the algorithm-only performance as a diagnostic aid.

7. The Type of Ground Truth Used (Test Set):

Ground Truth Type: Expert consensus based on "criteria consistent with the Universal Definition of Myocardial Infarction," adjudicated by an independent panel of expert physicians.

8. The Sample Size for the Training Set:

The document does not explicitly state a separate "training set" for the Access hsTnI assay in the context of machine learning or AI. Immunoassays like this are typically developed and validated using analytical studies (linearity, LoD, LoQ, interference, etc.) and then clinically validated.
The "99th percentile URL" study of 1088 healthy individuals and the "Clinical Performance" study of 1854 patients could be considered the primary data used for establishing reference ranges and clinical utility, analogous to validation data.

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

Given that this is an immunoassay and not an AI/ML-based diagnostic algorithm in the typical sense, there isn't a "training set" with ground truth established for machine learning.
For the 99th percentile URL study, the ground truth for "healthy" was established by excluding subjects with specific cardiovascular diseases, medications, diabetes, chronic kidney disease, other serious chronic diseases, acute infections, or pregnancy through survey and screening criteria.
For the clinical performance study, the ground truth for MI diagnosis was established by the independent panel of expert physicians based on the "Universal Definition of Myocardial Infarction," as described in point 7.

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Characteristic	Acceptance Criteria (New Device: Access hsTnI)	Predicate Device Performance (Access AccuTnl+3)	Reported Device Performance (Access hsTnI)
Intended Use/Indications for Use	Aid in the diagnosis of myocardial infarction (MI)	Aid in the diagnosis of myocardial infarction	Aid in the diagnosis of myocardial infarction (MI)
Assay Principle	Chemiluminescent sandwich immunoassay	Chemiluminescent sandwich immunoassay	Same
Test System	Automated immunoassay instrument	Automated immunoassay instrument	Same
Sample Type	Serum and heparinized plasma	Serum and heparinized plasma	Same
Reagent Pack configuration	Reagents ready to use and separated in a single reagent pack	Reagents ready to use and separated in a single reagent pack	Same
Primary Reagent Materials	Dynabeads paramagnetic particles coated with mouse monoclonal anti-human cTnI antibody	Solid phase magnetic particles, anti-cTnI antibodies	Dynabeads paramagnetic particles coated with mouse monoclonal anti-human cTnI antibody
Sample Volume	55µl	55µl	Same
Specific Reagent Materials	Sheep monoclonal anti-human cTnI alkaline phosphatase conjugate diluted in ACES buffered saline, with surfactant, BSA matrix, protein (bovine, sheep, mouse)	Mouse monoclonal anti-human cTnI alkaline phosphatase conjugate, magnetic particles coated with mouse monoclonal anti-human cTnI	Sheep monoclonal anti-human cTnI alkaline phosphatase conjugate diluted in ACES buffered saline, with surfactant, BSA matrix, protein (bovine, sheep, mouse)
Immunoassay Instrument	UniCel DxI 800 Access Immunoassay System	Access 2 Immunoassay System	UniCel DxI 800 Access Immunoassay System
Analytical Measuring Range	2.1 pg/mL to 27,027 pg/mL	0.02 ng/mL to 100 ng/mL (20 pg/mL to 100,000 pg/mL)	2.1 pg/mL to 27,027 pg/mL
Expected Results (Upper Reference Limit)	99th percentile of 17.9 pg/mL (Overall Lithium Heparin Plasma), 18.1 pg/mL (Overall Serum)	99th percentile of 0.02 with a 95% Confidence Interval (CI) of 0.01-0.05 ng/mL	99th percentile of 17.9 pg/mL (95% CI: 14.7-27.1) for Lithium Heparin Plasma 99th percentile of 18.1 pg/mL (95% CI: 14.3-25.6) for Serum
Precision	≤ 10% within-laboratory CV for concentrations ≥ 11.5 pg/mL, ≤ 1.15 pg/mL within-laboratory SD for concentrations < 11.5 pg/mL	Total CV of ≤8% at concentrations >0.075 ng/mL. SD ≤0.006 at concentrations ≤0.075 ng/mL	Within-laboratory (total) %CV: 2.8% to 10% for ≥ 11.5 pg/mL, SD: 0.22 to 0.75 for < 11.5 pg/mL
Open Reagent Pack Stability	Stable at 2 to 10°C for 64 days after initial use	Stable at 2 to 10°C for 56 days after initial use	Stable at 2 to 10°C for 64 days after initial use
Assay Protocol File (APF)	hsTnI APF with addition of the thermal algorithm	AccuTnI+3 APF with addition of the thermal algorithm	hsTnI APF with addition of the thermal algorithm
High-dose Hook Effect	No high-dose hook effect up to at least 2,000,000 pg/mL	(Not explicitly stated in table for predicate, but assumed critical)	No high-dose hook effect up to at least 2,000,000 pg/mL
Linearity	Linear across the range of the assay (2.1 to approximately 27,027 pg/mL) in both serum and lithium heparin plasma samples	(Not explicitly stated in table for predicate)	Linear across the range of the assay (2.1 to approximately 27,027 pg/mL) in both serum and lithium heparin plasma samples
Limit of Blank (LoB)	1.2 pg/mL	(Not explicitly stated in table for predicate)	1.2 pg/mL
Limit of Detection (LoD)	2.1 pg/mL	(Not explicitly stated in table for predicate)	2.1 pg/mL
Limit of Quantitation (LoQ)	4.6 pg/mL (CV ≤ 10%), 2.1 pg/mL (CV ≤ 20%)	(Not explicitly stated in table for predicate)	4.6 pg/mL (CV ≤ 10%), 2.1 pg/mL (CV ≤ 20%)
Analytical Specificity	No significant cross-reactivity (< 10% shift for > 11.5 pg/mL, < 2SD for ≤ 11.5 pg/mL)	(Not explicitly stated in table for predicate, but assumed critical)	No significant cross-reactivity (< 10% shift for > 11.5 pg/mL, < 2SD for ≤ 11.5 pg/mL)
Interfering Substances	No significant interference (< 10% shift for > 11.5 pg/mL, < 2SD for ≤ 11.5 pg/mL)	(Not explicitly stated in table for predicate, but assumed critical)	No significant interference (< 10% shift for > 11.5 pg/mL, < 2SD for ≤ 11.5 pg/mL)