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The Alkaline Phosphatase2 assay is used for the quantitation of alkaline phosphatase in human serum or plasma on the ARCHITECT c System.

Measurements of alkaline phosphatase or its isoenzymes are to be used as an aid in the diagnosis and treatment of liver, bone, parathyroid, and intestinal diseases.

The Alkaline Phosphatase2 assay is an automated clinical chemistry assay for the quantitation of alkaline phosphatase in human serum or plasma on the ARCHITECT c System. Alkaline Phosphatase in a sample catalyzes the hydrolysis of colorless para-nitrophenyl phosphate (p-NPP) to give para-nitrophenol (yellow phenoxide form at alkaline pH) and inorganic phosphate. The rate of absorbance increase at 404 nm is directly proportional to the alkaline phosphatase activity in the sample. Optimized concentrations of zinc and magnesium ions are present to activate the alkaline phosphatase in the sample.

The provided document is a 510(k) Premarket Notification for a clinical chemistry assay (Alkaline Phosphatase2) and does not describe an AI medical device. Therefore, the questions related to AI-specific acceptance criteria, ground truth establishment by experts, adjudication methods, multi-reader multi-case studies, and human-in-the-loop performance are not applicable.

The document focuses on the analytical performance of the Alkaline Phosphatase2 assay, demonstrating its substantial equivalence to a legally marketed predicate device. The information details various non-clinical performance studies to establish the device's reliability and accuracy for quantitating alkaline phosphatase in human serum or plasma.

Here's a breakdown of the relevant information from the document, tailored to the context of a diagnostic assay's performance evaluation, substituting the AI-specific questions with applicable details:

Acceptance Criteria and Device Performance for Alkaline Phosphatase2 Assay

This submission (K223317) is for a clinical chemistry assay, not an AI medical device. The acceptance criteria and performance studies are focused on the analytical performance of the assay to demonstrate its intended use for quantitative measurement of alkaline phosphatase.

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present a "table of acceptance criteria" for regulatory review, but it details various performance studies with implicit acceptance ranges. The reported device performance metrics are presented instead.

Performance Metrics of Alkaline Phosphatase2 Assay (Representative Values)

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

The "test set" in this context refers to the samples used in the analytical performance studies.

• Precision Studies: 2 controls and 4 human serum panels were tested. Each sample type had n=80 replicates in the within-laboratory precision study. For system reproducibility, 5 levels of controls were tested with n=90 replicates.
• Accuracy: 2 materials standardized to the IFCC reference method were used across 3 reagent lots and 2 instruments. The specific number of replicates per material is not explicitly stated but implied by the bias calculation.
• Lower Limits of Measurement (LoB, LoD, LoQ): n ≥ 60 replicates of zero-analyte or low-analyte level samples were used.
• Linearity: The study used a dilution series across the analytical measuring interval. The exact number of points or samples is not specified but is typical for CLSI EP06.
• Interference: Each interfering substance was tested at 2 analyte levels. The number of replicates per level is not specified.
• Method Comparison: n=145 (Calibration method) and n=143 (Calibration Factor method) serum samples were used to compare with the predicate device.
• Tube Type: Samples were collected from a minimum of 40 donors.

Data Provenance: Not explicitly stated as "country of origin," but the studies were conducted by Abbott Ireland Diagnostics Division. The studies are non-clinical laboratory studies (analytical performance), using human serum/plasma samples. The studies are inherently prospective in their execution, as they involve performing tests on collected samples according to pre-defined protocols (e.g., CLSI guidelines) to establish performance characteristics.

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

For an in vitro diagnostic (IVD) assay like this, "ground truth" is established by reference methods, certified reference materials, and established analytical principles, rather than expert human interpretation of images or clinical cases.

• Ground Truth Establishment: Clinical and Laboratory Standards Institute (CLSI) guidelines (e.g., EP05-A3, EP09-A3, EP17-A2, EP06, EP07, EP34) were meticulously followed for study design and data analysis.
• Expert Oversight: While not explicitly stated how many individual experts (e.g., clinical chemists) were involved in establishing the "ground truth" per se for the test samples, the studies adhere to recognized international standards and practices in clinical chemistry. The assumption is that qualified laboratory scientists and statisticians designed and executed these studies, and the reference methods themselves (like the IFCC reference method for Alkaline Phosphatase) are the "ground truth" standard.

4. Adjudication Method for the Test Set

Adjudication methods (like 2+1, 3+1) are typically used for subjective assessments, such as image interpretation. For a quantitative diagnostic assay, the "adjudication" is achieved through:

• Statistical Analysis: Rigorous statistical methods (e.g., Passing-Bablok regression for method comparison, precision calculations) are employed to analyze the quantitative results.
• Reference Methods and Materials: The "truth" is determined by comparing the device's measurements to established reference methods (e.g., IFCC reference method) or certified reference materials, which are inherently objective.
• CLSI Guidelines: Adherence to CLSI guidelines ensures standardized and robust experimental design and data interpretation, minimizing subjective bias.

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

Not applicable. This is an analytical performance study for an in vitro diagnostic assay, not an AI-assisted diagnostic tool involving human readers interpreting cases. Therefore, there is no MRMC study, and no effect size for human reader improvement with AI assistance.

6. Standalone Performance (Algorithm Only without Human-in-the-Loop)

This concept is less directly applicable but can be interpreted as the direct analytical performance of the instrument/reagent system. The presented non-clinical studies demonstrate the standalone performance of the Alkaline Phosphatase2 assay, meaning its performance characteristics (precision, accuracy, linearity, etc.) are evaluated intrinsically without direct human interpretation influencing the measurement itself. The human input is in setting up the test and interpreting the final quantitative result.

7. Type of Ground Truth Used

The ground truth for this diagnostic assay's performance evaluation largely relies on:

• Reference Methods: Specifically, the IFCC reference method for Alkaline Phosphatase is cited for accuracy studies.
• Certified Reference Materials: Standardized materials are used for calibration and accuracy verification.
• Statistical Definitions: For LoB, LoD, LoQ, and precision, the "ground truth" is established through statistical definitions based on replicate measurements of samples with known (or zero) analyte concentrations.
• Predicate Device Comparison: The predicate device's performance also serves as a comparative "ground truth" to demonstrate substantial equivalence, although the goal is to align with the IFCC standard.

8. Sample Size for the Training Set

Not applicable. This is a traditional IVD assay, not an AI model requiring a "training set" in the machine learning sense. The assay works based on established chemical principles, not on learned patterns from a large dataset. The reagent formulation and instrument algorithms are developed using R&D processes, not machine learning training.

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

Not applicable, as there is no "training set" in the context of an AI/ML model for this diagnostic device. The "truth" for developing such an assay would be based on fundamental chemical and biological understanding, robust experimental data from R&D, and adherence to analytical standards.

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