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The Hitachi Clinical Analyzer S TEST reagent cartridge CRP is intended for the quantitative measurement of C-reactive protein in serum, lithium heparin plasma, K3 EDTA plasma, and sodium citrate plasma. The test system is intended for use in clinical laboratories or physician office laboratories. CRP measurements aid in the evaluation of injury to body tissues, and infection and inflammatory disorders. For in vitro diagnostic use only.

The Hitachi Clinical Analyzer is an automatic, bench-top, wet chemistry system intended for use in clinical laboratories or physician office laboratories. The instrument consists of a desktop analyzer unit, an operations screen that prompts the user for operation input and displays data, a printer, and a unit cover. The analyzer unit includes a single probe, an incubation rotor, carousels for sample cups and reagent cartridges, and a multi-wavelength photometer. The single-use reagent cartridges may be placed in any configuration on the carousel, allowing the user to develop any test panel where the reagent cartridges are available. The S TEST reagent cartridges are made of plastic and include two small reservoirs capable of holding two separate reagents (R1 and R2), separated by a reaction cell/photometric cuvette. The cartridges also include a dot code label that contains all chemistry parameters, calibration factors, and other production-related information, e.g., expiration dating. The dimensions of the reagent cartridges are: 13.5 mm (W) x 28 mm (D) x 20.2 mm (H). System operation: After the sample cup is placed into the carousel, the analyzer pipettes the sample, pipettes the reagent, and mixes (stirs) the sample and reagent together. After the sample and reagent react in the incubator bath, the analyzer measures the absorbance of the sample, and based on the absorbance of the reactions, it calculates the concentration of analyte in the sample. The test system can measure analytes in serum or plasma and results are available in approximately 15 minutes per test. This submission is for reagent cartridge test systems for CRP. Chemistry reactions: CRP in samples causes an antigen-antibody reaction with latex sensitizes with Goat antihuman C-Reactive Protein antibody to induce agglutination. The concentration of CRP can be determined by measuring this agglutination as the amount of change in absorbance. CRP + Goat anti-human C-reactive protein antibody coated latex -> Agglutination due to antigen-antibody reaction

This document describes the Hitachi Clinical Analyzer S TEST Reagent Cartridge CRP, a device for measuring C-reactive protein.

1. Table of Acceptance Criteria & Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" but rather presents a series of performance studies with their results. I will infer typical acceptance ranges for these metrics based on common laboratory standards and the context of the predicate device.

Note regarding Acceptance Criteria: The document explicitly lists "no interference" for interference testing with a recovery range of 90-110%. For other metrics, the acceptance criteria are inferred based on the provided data, predicate device performance, and common regulatory expectations for in vitro diagnostic devices.

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

• The document describes various studies, and the "test set" here refers to the samples used in these performance evaluations, rather than a specific validation test set for an AI algorithm.

  • Analytical Sensitivity (Limits of Detection): Sample size not explicitly stated for this particular study, but the methodology followed CLSI EP17-A.
  • Linearity: Sample size not explicitly stated for this particular study, but the methodology followed CLSI EP-6A. Range of linearity 1 to 154 mg/L was found.
  • 20-day In-house Precision: Three levels of samples tested over 20 days. Each level was tested in two runs, twice a day. This implies 80 measurements per level (2 runs/day * 2 times/day * 20 days), but the summary tables show mean, SD, %CV for "Total" precision, suggesting consolidated results.
  • Interference Testing: Two serum pools with approximately 12 mg/L and 80 mg/L C-reactive protein were used.
  • Method Comparison (In-house): 88 clinical specimens.
  • Matrices Comparisons: 45 matched serum/plasma samples.
  • External Site Precision (Clinical Study): Three blinded serum samples (low, middle, high CRP concentrations) were assayed six times per day for five days at each of three sites, resulting in 30 replicates per level per site.
  • Method Comparison (Clinical Study - POL Sites): Approximately 55 serum specimens (56 for Sites 1 & 2, 55 for Site 3).

• Data Provenance: The document does not explicitly state the country of origin for the clinical or non-clinical samples. However, the external studies were conducted at "three external POL-type sites," implying a clinical setting within the United States market for which the device is being cleared. The method comparison refers to "clinical specimens." The studies are retrospective in the sense that they use collected samples to establish performance characteristics for the device itself rather than following a patient cohort prospectively.

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

This device is an in vitro diagnostic (IVD) test for quantitative measurement of C-reactive protein. For such devices, "ground truth" is typically established by:

• Reference methods (e.g., a "standard laboratory system" or "comparative method" mentioned in the document).
• Certified reference materials.
• Highly qualified laboratory personnel following standardized protocols.

The document does not mention the use of experts in the traditional sense of medical image interpretation (e.g., radiologists) to establish ground truth for this type of chemical assay. The "ground truth" for the method comparison studies was derived from a "standard laboratory system" or a "comparative method," which would be another FDA-cleared or gold-standard CRP assay administered by qualified laboratory professionals. The qualifications of these professionals are not detailed, but it's understood they would be trained lab technicians/scientists.

4. Adjudication Method for the Test Set:

Not applicable. As this is a quantitative in vitro diagnostic assay, there is no "adjudication method" in the sense of multiple human readers resolving disagreements. Performance is determined by comparing the device's quantitative output against either a reference method's quantitative output or known concentrations in control materials.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance:

Not applicable. This device is an in vitro diagnostic assay measuring C-reactive protein, not a medical imaging AI device involving human readers. There is no AI component or human-in-the-loop performance described.

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

Not applicable. This device is an automated in vitro diagnostic instrument with reagent cartridges. Its performance is inherently "standalone" in the sense that it performs a chemical analysis and provides a quantitative result without human interpretive input beyond sample loading and result review. There is no separate "algorithm" for distinct standalone performance that would typically be distinguished from a human-in-the-loop scenario. The performance metrics presented (precision, linearity, method comparison) are its standalone performance.

7. The Type of Ground Truth Used:

The ground truth for the device's performance claims was established through:

• Reference methods: For method comparison studies, the Hitachi system's results were compared against an "standard laboratory system" (in-house validation) or a "comparative method" (external POL validation). These reference methods serve as the de-facto ground truth for assessing performance.
• Known concentrations: For studies like linearity, analytical sensitivity, and precision, samples with known or well-characterized concentrations of CRP (e.g., control materials, spiked samples, reference materials) are used.
• Certified protocols: The studies followed established clinical laboratory standards (CLSI guidelines: EP17-A, EP-6A, EP5-A2, EP7-A2, EP9-A2), which dictate how ground truth is appropriately established for these types of assays.

8. The Sample Size for the Training Set:

Not applicable. This device is a diagnostic assay, not an AI/machine learning algorithm that requires a "training set" in the computational sense. The device's operational parameters and performance were likely optimized during its development using various samples, but these are not referred to as a "training set" in this context. The "nonclinical data" and "clinical data" sections describe validation studies, not training.

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

Not applicable (as there is no "training set" in the AI/ML context). As described in point #7, ground truth for the performance evaluation was established using reference laboratory methods, known concentrations, and adherence to CLSI guidelines.

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