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The Sigma Diagnostics INFINITY™ Uric Acid Reagent is intended for the in vitro quantitative, diagnostic determination of uric acid in human serum, plasma or urine on both automated and manual systems.

The Sigma Diagnostics INFINJTY™ Uric Acid Reagent is a device intended to measure uric acid in serum, plasma or urine. Measurements obtained by the device are used in the diagnosis and treatment of numerous renal and metabolic disorders, including renal failure, gout, leukemia, psoriasis, starvation or other wasting conditions, and of patients receiving cytotoxic drugs.

This reagent is based upon the methods of Trivedi and Kabasakalland with a modified Trinder peroxide assay using 2,4,6-Tribromo-3-hydroxy benzoic acid (TBHB).

The series of reactions involved in the assay system is as follows:

• Uric Acid is oxidized to allantoin by uricase with the production of H2O2. 1 .
  Uric Acid + O2 + H2O _ Uricase _ Allantoin + CO2 + H2O2

• The peroxide reacts with 4-aminoantipyrine (4-AAP) and TBHB in the presence of 2. peroxidase to yield a quinoneimine dye. The resulting change in absorbance at 520 nm (500-550 nm) is proportional to uric acid concentration in the sample.
  HoOs + 4-AAP + TBHB Peroxidase \ Ouinoneimine + H2O

Here's a breakdown of the acceptance criteria and study information for the Sigma Diagnostics INFINITY™ Uric Acid Reagent, Procedure 684, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

Note: For an in vitro diagnostic (IVD) like this, specific analytical performance characteristics (e.g., precision, accuracy, linearity, lower limit of detection, upper limit of quantitation, interference) would typically be detailed in the full 510(k) submission but are not explicitly presented as acceptance criteria or reported performance values in this summary. The submitted information focuses on substantial equivalence to a predicate.

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

• Test Set Sample Size: 126 samples were used for the correlation study.
• Data Provenance: The document does not specify the country of origin of the data. It also does not explicitly state whether the data was retrospective or prospective. Given the nature of a correlation study comparing a new reagent to an existing one, it's generally conducted prospectively using fresh or banked clinical samples. The use of "plasma samples" suggests human biological samples.

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

This information is not applicable and not provided in the document.

For an IVD like a uric acid reagent, the "ground truth" for the test set is established by the reference method (the predicate device, in this case, Sigma Diagnostics Uric Acid Reagent, Procedure No. 685). The accuracy of the predicate device is assumed based on its prior clearance and validation. Clinical experts are not typically involved in establishing the "ground truth" for individual quantitative measurements in such a direct comparison study; instead, the existing, validated method serves as the comparator.

4. Adjudication Method for the Test Set

This information is not applicable and not provided in the document.

Adjudication methods (like 2+1, 3+1) are typically used in studies involving subjective interpretations (e.g., image-based diagnosis) where multiple human readers assess cases and a consensus or tie-breaking mechanism is needed to establish ground truth. For a quantitative chemical assay, the comparison is directly between the numerical results of two different analytical methods.

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

This information is not applicable and not provided in the document.

MRMC studies and the concept of "human readers improving with AI assistance" pertain to artificial intelligence (AI) systems designed to aid human interpretation, particularly in image analysis. This document describes a chemical reagent for quantitative laboratory measurement, not an AI-assisted diagnostic tool for subjective human interpretation.

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

This information is not applicable and not provided in the document, as it describes a chemical reagent, not a software algorithm. The "device performance" refers to the analytical performance of the reagent system.

7. The Type of Ground Truth Used

The "ground truth" for the correlation study was the measurement of uric acid levels obtained by the predicate device, Sigma Diagnostics Uric Acid Reagent, Procedure No. 685 (K853357). This can be considered a form of reference method comparison or comparative measurement data.

8. The Sample Size for the Training Set

This information is not applicable and not provided in the document.

Chemical reagents like this do not typically have "training sets" in the sense of machine learning algorithms. Their performance characteristics are established through analytical validation studies (e.g., linearity, precision, accuracy, interference studies) and then compared to a predicate using clinical samples (the "test set" in this context). The formulation and optimization of the reagent itself would involve R&D, but not a "training set" of data in the AI sense.

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

This information is not applicable and not provided in the document for the reasons stated in point 8.

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