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For in vitro diagnostic use with the CARESIDE Analyzer™ to measure ammonia from anti-coagulated whole blood or plasma specimens to aid in the diagnosis and treatment of patients with severe liver disorders such as cirrhosis, hepatitis, and Reye's syndrome.

CARESIDE™ Ammonia cartridges are used with the CARESIDE Analyzer™ to measure ammonia in anti-coagulated whole blood or plasma specimens. The CARESIDE™ Ammonia cartridge, a single use disposable in vitro diagnostic test cartridge, delivers a measured volume of plasma to a dry film to initiate the measurement of ammonia The film cartridge (patent pending) contains all reagents necessary to measure ammonia.

Each CARESIDE™ Ammonia cartridge consists of an ammonia-specific multi-layer reagent film mounted in a plastic base with a hinged lid. The user introduces the specimen into the cartridge Sample Well, closes the lid and inserts the cartridge into the CARESIDE Analyzer™.

Once loaded, the CARESIDE Analyzer™ scans the cartridge barcode, brings the cartridge and the contained specimen to 37°C, and spins the cartridge to move the sample from the Sample Well into the cartridge channels and chambers. 8.5 microliters of sample remains in the metering passage. Any excess sample flows into the Overflow Well.

The 8.5 microliters of sample is automatically dispensed onto the multi-layer reagent film. The spreading layer distributes the sample evenly on the film before the sample moves through the reaction, porous, and detection layers where a blue-green dye forms in the presence of ammonia. The color intensity of the resulting blue-green dye, as measured by the amount of reflected light at 590 nanometers, directly relates to the ammonia concentration of the specimen.

As the cartridges spin, a photodiode measures reflectance of light emitted by a wavelength-specific light emitting diode (LED) over a fixed time period. The analyzer uses the reflectance measurements and the lot-specific standard curve to calculate ammonia concentration.

Here's an analysis of the acceptance criteria and study information for the CARESIDE™ Ammonia device, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

It's important to note that the provided text does not explicitly state pre-defined acceptance criteria in terms of thresholds for satisfactory performance. Instead, it presents the comparative performance characteristics of the CARESIDE™ Ammonia device alongside the predicate device (Vitros NH3 DT Slides) and implicitly argues for substantial equivalence based on these comparisons.

Therefore, the "acceptance criteria" listed below are inferred from the demonstrated performance and the context of establishing substantial equivalence to a legally marketed predicate device. The underlying acceptance is likely that the device performs as well as or better than the predicate device for key analytical metrics.

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

• Test Set Sample Size: The document does not explicitly state the sample size used for the performance comparison studies (accuracy, precision, method comparison, linearity, interference).
• Data Provenance: Not specified in the provided text (e.g., country of origin, retrospective or prospective).

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

• This information is not provided in the text. As an in vitro diagnostic device for quantitative measurement, the "ground truth" would typically come from a reference method of known accuracy rather than expert interpretation of images or clinical findings.

4. Adjudication Method for the Test Set

• This information is not applicable for this type of analytical device performance study, which relies on quantitative measurements and comparison to a reference method, rather than subjective expert adjudication.

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

• No, a MRMC comparative effectiveness study was not done. This type of study is relevant for imaging devices or diagnostic tests that involve human interpretation of results. The CARESIDE™ Ammonia device is an automated, quantitative in vitro diagnostic, so human "readers" are not directly involved in interpreting the result to the same extent as in, for example, radiology.

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

• Yes, a standalone performance study was done. The entire "Comparative Performance Characteristics" section describes the performance of the CARESIDE™ Ammonia device (algorithm/system only) in generating quantitative results. The device measures ammonia automatically and provides a µmol/L NH3 value. There is no indication of human intervention or interpretation required during the test process itself.

7. Type of Ground Truth Used

• The ground truth for the performance studies was established using a reference method, specifically the Glutamate dehydrogenase method. This is explicitly stated as the "Reference Method." For the method comparison study, it was compared against a "RAICHEM" method, suggesting another established analytical method.

8. Sample Size for the Training Set

• This information is not provided in the text. The document describes a specific analytical method and its performance, but not the development or "training" of an algorithm in the sense of machine learning, which would typically involve a separate training set. The "standard curve" is mentioned as lot-specific, which is a form of calibration rather than algorithm training with a large dataset.

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

• This information is not provided as a "training set" in the context of machine learning algorithms is not discussed. For traditional analytical devices like this, calibration (which uses a set of known standards to establish the relationship between signal and concentration) is the equivalent of "training," and the ground truth for this would be the precisely known concentrations of the calibrator materials. The text notes "# Calibration information bar-coded on each cartridge. Calibration information may change with each lot." This implies known calibrator values are used for establishing the standard curve.

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