(50 days)
The Ammonia assay is used for the quantitation of ammonia in human plasma.
The Ethyl Alcohol Clinical Standard Solutions are intended for use in the calibration and standardization of instruments and methods for the determination of ethyl alcohol in whole blood or serum. The Standard Solutions may also be used for validation of the laboratory's routine standards and/or control materials.
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 NHzDPH. These reactions, catalyzed by glutamate dehydrogenase (GLDH), produce glutamate and NH2DP*. The oxidation of NHxDPH produces a decrease in absorbance at 340 nm which is directly proportional to the concentration of ammonia in the sample.
Here's a breakdown of the acceptance criteria and study information based on the provided text, focusing on the Ammonia assay (K981926):
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Acceptance Criteria (from predicate) | Reported Device Performance (Ammonia assay) |
|---|---|---|
| Method Comparison | Correlation with predicate device | Correlation coefficient = 0.9957 |
| Slope relative to predicate | Slope = 0.971 | |
| Y-intercept relative to predicate | Y-intercept = -2.083 umol/L | |
| Precision | %CV (Within-run, Between-run, Between-day) | 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 | Maximum quantifiable range | Linear up to 1,574.9 umol/L |
| Limit of Quantitation (Sensitivity) | Minimum quantifiable concentration | 20.6 umol/L |
2. Sample Size Used for the Test Set and Data Provenance
The document does not specify the exact sample size used for the method comparison or precision studies. It mentions "Comparative performance studies were conducted" and "Precision studies were conducted using three levels of control material," but no specific number of patient samples or replicates are given.
The data provenance is not explicitly stated (e.g., country of origin). Since it's a 510(k) submission to the FDA, it is highly likely the studies were conducted in the US, but this is not confirmed in the text. The studies appear to be prospective as performance characteristics were "conducted" using the new device and compared to a predicate.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
This information is not applicable to this type of in vitro diagnostic device (IVD) study. The ground truth for quantitative assays like ammonia is established by the reference method (the predicate device in this case) or by well-characterized control materials, not by expert consensus on interpretations.
4. Adjudication Method for the Test Set
This is not applicable. Adjudication methods like "2+1" or "3+1" are typically used in clinical imaging or diagnostic studies where human interpretation of results is involved, and there's a need to resolve discrepancies. For this quantitative IVD, the comparison is direct numerical measurement against a predicate.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size
This is not applicable. MRMC studies are used for assessing the performance of human readers, often aided by AI, in interpreting diagnostic images or data. The Ammonia assay is a fully automated quantitative measurement, not requiring human interpretation of visual or complex data in the same way.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies described are standalone performance studies for the Ammonia assay. The device directly measures ammonia concentrations without human intervention in the interpretive process. The "performance characteristics" outlined (method comparison, precision, linearity, sensitivity) all evaluate the algorithmic and analytical performance of the device itself.
7. The Type of Ground Truth Used
The primary ground truth used is the performance of the predicate device, the A-GENT® Ammonia assay on the ABBOTT SPECTRUM® Series II™ System. For precision, well-characterized control materials at three different levels were used as ground truth.
8. The Sample Size for the Training Set
The document does not provide information on a separate training set. For in vitro diagnostic assays of this nature, especially those based on established chemical reactions, there isn't typically a "training set" in the machine learning sense. The assay is developed and validated based on the underlying chemical principles and established analytical performance characteristics.
9. How the Ground Truth for the Training Set Was Established
As no "training set" is described for this IVD, this information is not applicable. The development of such an assay relies on well-understood chemical principles and rigorous analytical validation rather than data-driven machine learning training.
§ 862.3200 Clinical toxicology calibrator.
(a)
Identification. A clinical toxicology calibrator is a device intended for medical purposes for use in a test system to establish points of reference that are used in the determination of values in the measurement of substances in human specimens. A clinical toxicology calibrator can be a mixture of drugs or a specific material for a particular drug (e.g., ethanol, lidocaine, etc.). (See also § 862.2 in this part.)(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9.