(26 days)
The ACE Magnesium Reagent is intended for the quantitative determination of magnesium concentration in serum using the ACE Axcel Clinical Chemistry System. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low serum levels of magnesium) and hypermagnesemia (abnormally high serum levels of magnesium). This test is intended for use in clinical laboratories or physician office laboratories. For in vitro diagnostic use only.
Magnesium ions in serum react with Xylidyl blue-1 in an alkaline medium to produce a red complex which is measured bichromatically at 525 nm/692 nm. The intensity of color produced is directly proportional to the magnesium concentration in the sample. EGTA prevents calcium interference by preferential chelation of calcium present in the sample. A surfactant system is included to remove protein interference.
The ACE Axcel Clinical Chemistry System consists of two major components, the chemistry instrument and an integrated Panel PC. The instrument accepts the physical patient samples, performs the appropriate optical or potentiometric measurements on those samples and communicates that data to an integral Panel PC. The Panel PC uses keyboard or touch screen input to manually enter a variety of data, control and accept data from the instrument, manage and maintain system information and generate reports relative to patient status and instrument performance. The Panel PC also allows remote download of patient requisitions and upload of patient results via a standard interface.
Here's a breakdown of the acceptance criteria and study information for the ACE Magnesium Reagent based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria values (e.g., "The CV must be less than X%"). Instead, it reports the performance values achieved by the device. The "acceptance criteria" are implied by the reported performance being deemed sufficient for substantial equivalence.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Precision | Satisfactory CV values | Within-run CV: 1.9% to 6.7% (≥21 days) |
| Total CV: 2.8% to 7.5% (≥21 days) | ||
| POL (within-run CV): 1.2% to 5.4% (5 days) | ||
| POL (total CV): 1.4% to 5.8% (5 days) | ||
| Accuracy | Satisfactory correlation coefficient, SE estimate, and confidence intervals for slope and intercept | Correlation Coefficient: 0.9735 (110 samples) |
| Standard Error Estimate: 0.14 (110 samples) | ||
| Confidence Interval Slope: 1.000 to 1.092 (110 samples) | ||
| Confidence Interval Intercept: -0.28 to -0.08 (110 samples) | ||
| POL Correlation Coeff: 0.9919 to 0.9959 | ||
| POL SE Estimate: 0.09 to 0.14 | ||
| POL Conf. Interval Slope: 1.001 to 1.086 | ||
| POL Conf. Interval Intercept: -0.10 to 0.15 | ||
| Detection Limit | Acceptable detection limit | 0.3 mg/dL |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Accuracy Test Set: 110 samples for the primary correlation study.
- Sample Size for Precision Test Set: Not explicitly stated as a count of individual samples, but "four magnesium levels for ≥21 days" and "three separate Physician Office Laboratory (POL) sites over 5 days" implies multiple measurements across different samples or levels.
- Data Provenance: The document does not specify the country of origin. It conducted studies "at four magnesium levels" and "at three separate Physician Office Laboratory (POL) sites," suggesting internal testing and potentially external POL sites. The studies are retrospective as they involve analyzing samples for performance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document describes an in vitro diagnostic reagent for quantitative determination of magnesium. The ground truth for such devices is established by comparison to a reference method or predicate device, not by expert interpretation of images or clinical assessments.
- Number of Experts: Not applicable in the context of this type of diagnostic device.
- Qualifications of Experts: Not applicable.
4. Adjudication Method for the Test Set
Not applicable for this type of quantitative diagnostic device. Ground truth is established by comparing the device's output to a known reference method or another validated device (the predicate).
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
- MRMC Comparative Effectiveness Study: No, this is not an AI/human reader study. This document describes a chemical reagent for an automated clinical chemistry system.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
Yes, the performance data presented (precision, accuracy, detection limit) are for the ACE Magnesium Reagent operating on the ACE Axcel Clinical Chemistry System in a standalone manner. The measurements are automated, and the results are quantitative values obtained directly from the system.
7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)
The ground truth for the accuracy study was established by comparing the results from the ACE Magnesium Reagent on the ACE Axcel Clinical Chemistry System against the results from the predicate device, the "Alfa Wassermann ACE Clinical Chemistry System."
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning or AI. For an in vitro diagnostic reagent, the development process involves formulating the reagent and optimizing its performance characteristics. The validation studies (precision, accuracy, detection limit) on the ACE Axcel Clinical Chemistry System served as the testing of the final product, not a training set for an algorithm.
9. How the Ground Truth for the Training Set was Established
Not applicable, as this is not an AI/machine learning device with a distinct training set in that sense. The "ground truth" during the development and validation phase would be derived from known-concentration controls, reference materials, and comparative analysis against established methods (like the predicate device).
§ 862.1495 Magnesium test system.
(a)
Identification. A magnesium test system is a device intended to measure magnesium levels in serum and plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of magnesium).(b)
Classification. Class I.