Search Results

The Ammonia Ultra is intended for the in vitro quantitative determination of Ammonia (NH3) in human plasma. Ammonia measurements are used in the diagnosis and treatment of severe liver disorders such as cirrhosis, hepatitis and Reye's syndrome. The Ammonia Controls are intended as a means of monitoring Sentinel Ammonia Ultra assay method.

The Sentinel Ammonia Ultra Diagnostic Assay described in this 510(k) submission is composed by reagent, calibrator and controls, packaged and distributed in different kits. The device is intended to be sold as an in-vitro test for professional use. The Ammonia Ultra is an enzymatic in vitro diagnostic assay for the quantitative determination of ammonia in human plasma. Ammonia, in the presence of glutamate dehydrogenase (GLDH), combines with alpha-ketoglutarate and NADH to yield glutamate and NAD*. The decrease in absorbance due to the NADH oxidation, at 340 nm, is proportional to the ammonia concentration in the examined plasma. The reagent contains lactate dehydrogenase (LDH) in excess, to rapidly reduce endogenous pyruvate so that it does not interfere with the assay system. The actual concentration of ammonia is determined multiplying the rate of absorbace per the calibration factor obtained during the calibration with the ammonia standard of 500 microgram/dL included in the kit. To ensure a correct determination during quantification of ammonia samples, a quality control procedure is required. The Ammonia Controls are liquid controls at 3 levels, prepared in bovine albumin matrix, and are used to verify the performance of the Ammonia Ultra assay. The value and range assigned to each level is specific for each lot and has been determined in rigorously standardized condition by the calculation of the median obtained in multiple determinations using reagents and standard relative to the Ammonia Ultra.

This document describes the Sentinel Ammonia Ultra Diagnostic Assay, an in-vitro diagnostic device for the quantitative determination of ammonia in human plasma. The information provided in the 510(k) summary focuses on demonstrating substantial equivalence to predicate devices rather than detailing specific acceptance criteria and the comprehensive study results to prove device performance against those criteria. Therefore, several requested categories cannot be fully addressed from the provided text.

Here's the available information:

1. A table of acceptance criteria and the reported device performance

The document does not explicitly state pre-defined acceptance criteria with numerical targets. Instead, it mentions that "Performance evaluations included sensitivity, intra- and inter-assay imprecision, and method comparison." The conclusion states that "The performance and safety data presented in this premarket notification support a finding of substantial equivalence between the Sentinel Ammonia Ultra Diagnostic Assay and the predicate devices specified in this submission." This implies that the performance measured for sensitivity, imprecision, and method comparison was deemed acceptable relative to the predicate devices. Without the full study report, specific acceptance criteria and detailed quantitative performance values are not available.

2. Sample sized used for the test set and the data provenance

The document does not specify the sample sizes used for sensitivity, intra- and inter-assay imprecision, or method comparison studies. It also does not provide information on the data provenance (e.g., country of origin, retrospective or prospective nature).

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

This information is not provided in the document. The "ground truth" for an in-vitro diagnostic device like this would typically be established by a reference method or known concentrations of ammonia in control samples. Expert interpretation of results is usually less relevant than the analytical accuracy against a gold standard.

4. Adjudication method for the test set

This information is not provided. Adjudication methods are typically used in studies involving human interpretation or subjective assessments, which are not the primary focus for an enzymatic in-vitro diagnostic assay's performance evaluation.

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

An MRMC study is not applicable to this device. This is an in-vitro diagnostic assay for quantitative determination of ammonia, meaning there are no "human readers" or "AI assistance" involved in interpreting results in the way they would be in an imaging or diagnostic support system. Its performance is based on analytical accuracy.

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

This device is a standalone algorithm (an enzymatic assay, which functions like an algorithm in its chemical reactions and measurement). Its performance is inherently "standalone" in the context of its operation (i.e., it determines ammonia concentration without human-in-the-loop interpretation influencing the measurement result itself). The performance studies mentioned (sensitivity, imprecision, method comparison) would be a direct assessment of its standalone capability.

7. The type of ground truth used

For an in-vitro diagnostic device measuring a specific analyte like ammonia, the "ground truth" for performance evaluations would generally be:

• Known concentrations: For sensitivity and imprecision, this would involve using commercially available or custom-prepared control samples with a precisely known concentration of ammonia.
• Reference method comparison: For method comparison, it would involve testing patient samples using both the Sentinel Ammonia Ultra Diagnostic Assay and a legally marketed, well-established reference method (predicate device in this case) or a recognized gold standard method to assess concordance.

The document states that "The reagent contains lactate dehydrogenase (LDH) in excess, to rapidly reduce endogenous pyruvate so that it does not interfere with the assay system. The actual concentration of ammonia is determined multiplying the rate of absorbace per the calibration factor obtained during the calibration with the ammonia standard of 500 µg/dL included in the kit." This implies using a calibrated standard for accurate quantification, which serves as a form of ground truth for instrument calibration.

8. The sample size for the training set

The concept of a "training set" in the context of machine learning is not directly applicable to this enzymatic in-vitro diagnostic assay. These assays are based on established biochemical reactions, and their performance is optimized through reagent formulation, calibration, and validation, not typically through machine learning model training on large datasets in the conventional sense. Therefore, no "training set sample size" is reported.

9. How the ground truth for the training set was established

As explained above, there isn't a "training set" in the machine learning sense for this type of device. The accuracy of the assay is based on the chemical principle (enzymatic reaction converting NADH) and the use of a calibrated standard (500 µg/dL ammonia standard) to establish the relationship between absorbance change and ammonia concentration.

Ask a specific question about this device