(51 days)
The Ammonia assay is used for the quantitation of ammonia in human plasma. Ammonia measurements are used in the diagnosis and treatment of severe liver disorders, such as cirrhosis, hepatitis, and Reye's syndrome.
Ammonia is an in vitro diagnostic assay for the quantitative determination of ammonia in human plasma. The Ammonia assay is a clinical chemistry assay which utilizes the amination of x-ketoglutarate by ammonia (NH3) along with the concomitant oxidation of NH2DPH. These reactions, catalyzed by glutamate dehydrogenase (GLDH), produce glutamate and NHxDP+ The oxidation of NHxDPH produces a decrease in absorbance at 340 nm which is directly proportional to the concentration of ammonia in the sample.
The provided document K981920 describes the Abbott Laboratories Ammonia (Amm) assay. This is an in vitro diagnostic assay for the quantitative determination of ammonia in human plasma, used in the diagnosis and treatment of severe liver disorders. This device is not an AI/ML powered device, therefore, some of the requested information (e.g. effect size of human readers with vs without AI assistance) is not applicable.
Here's a breakdown of the acceptance criteria and study information:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Ammonia assay are implicitly stated by its substantial equivalence to the predicate device, the A-GENT® Ammonia assay (K870787) on the ABBOTT SPECTRUM® Series II™ System. The performance characteristics of the Ammonia assay are presented and deemed "acceptable" and "substantially equivalent" when compared to the predicate.
| Performance Metric | Acceptance Criteria (Implied by Substantial Equivalence to Predicate) | Reported Device Performance |
|---|---|---|
| Method Comparison | Acceptable correlation with predicate device | Correlation Coefficient = 0.9957 |
| Slope = 0.971 | ||
| Y-intercept = -2.083 umol/L | ||
| Precision | Acceptable within-run, between-run, and between-day precision | Level 1/Panel 103: 11.7% Total %CV |
| Level 2/Panel 104: 4.0% Total %CV | ||
| Level 3/Panel 105: 5.5% Total %CV | ||
| Linearity | Acceptable linearity up to a specified concentration | Linear up to 1,574.9 umol/L |
| Limit of Quantitation (Sensitivity) | Acceptable sensitivity | 20.6 umol/L |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the sample size used for the test set in terms of the number of patient samples. It mentions "Comparative performance studies were conducted using the AEROSET™ System" and "Precision studies were conducted using the Ammonia assay... using three levels of control material."
- Sample Size: Not explicitly stated for patient equivalence studies. For precision studies, it mentions "three levels of control material." The number of replicates or runs for these controls is not specified.
- Data Provenance: Not explicitly stated. There is no information regarding the country of origin of the data or whether the studies were retrospective or prospective.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
Not applicable. This device is a quantitative diagnostic assay. The "ground truth" for method comparison and precision is typically established by the reference method (predicate device) and analytical standards, respectively, rather than by human expert consensus or adjudication.
4. Adjudication Method for the Test Set
Not applicable. As a quantitative assay, adjudication by experts for ground truth is not relevant.
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
Not applicable. This is an in vitro diagnostic assay, not an AI/ML powered device that would involve human readers interpreting results with or without AI assistance.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, in essence, the described performance characteristics (method comparison, precision, linearity, sensitivity) represent the standalone performance of the Ammonia assay without human intervention influencing the measurement itself. The output is a quantitative value.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
For the comparative performance studies, the "ground truth" was established by the predicate device, the A-GENT® Ammonia assay on the ABBOTT SPECTRUM® Series II™ System. The goal was to show similarity in results.
For precision, linearity, and sensitivity, the ground truth is based on analytical standards and control materials with known concentrations.
8. The Sample Size for the Training Set
Not applicable. This diagnostic assay is not an AI/ML model that requires a "training set." It is a chemical-based assay.
9. How the Ground Truth for the Training Set was Established
Not applicable. As this is not an AI/ML model, there is no training set or ground truth in that context.
§ 862.1065 Ammonia test system.
(a)
Identification. An ammonia test system is a device intended to measure ammonia levels in blood, serum, and plasma, Ammonia measurements are used in the diagnosis and treatment of severe liver disorders, such as cirrhosis, hepatitis, and Reye's syndrome.(b)
Classification. Class I.