(67 days)
The ATAC PAK Magnesium Reagent Kit is intended for use with the ATAC Calibrator and the ATAC 8000 Random Access Chemistry System as a system for the quantitative determination of magnesium in serum and plasma. Magnesium results are used for the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of magnesium).
The ATAC PAK Magnesium Reagent determines magnesium through its selective binding by xylidyl blue to form a red-purple chelate. The resulting increase in absorbance at 510 nm is proportional to the magnesium concentration in the sample.
The provided text describes the ATAC PAK Magnesium Reagent Kit, its intended use, and studies demonstrating its performance and substantial equivalence to a predicate device.
Here's an analysis of the acceptance criteria and study information:
Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in a tabulated format. However, it presents performance metrics that implicitly serve as acceptance criteria by demonstrating equivalence to a legally marketed device and adequate performance for its intended use. Based on the provided data, the implicit acceptance criteria and the device's performance are summarized below:
| Performance Metric | Implicit Acceptance Criteria (based on predicate or desired performance) | Reported Device Performance |
|---|---|---|
| Linearity | Linear recovery over the usable range for magnesium determination. | Linear from 0.1 to 5.5 mEq/L. ATAC Recoveries = 0.0 mEq/dL + 0.983 x (Standard Value), r = 0.996, sY.x = 0.15 mEq/L, n = 36 |
| Precision (Within Run) | Low coefficient of variation (CV%) for replicate assays. | Serum 1: 1SD = 0.09 (8.8% CV) at 1.0 mEq/L |
| Serum 2: 1SD = 0.10 (5.2% CV) at 1.9 mEq/L | ||
| Serum 3: 1SD = 0.12 (4.1% CV) at 2.8 mEq/L | ||
| Precision (Total) | Low coefficient of variation (CV%) for replicate assays over time. | Serum 1: 1SD = 0.12 (12.0% CV) at 1.0 mEq/L |
| Serum 2: 1SD = 0.13 (7.1% CV) at 1.9 mEq/L | ||
| Serum 3: 1SD = 0.15 (5.4% CV) at 2.8 mEq/L | ||
| Method Comparison (Correlation with Predicate) | Good correlation with a commercially available method. | ATAC 8000 = 0.04 mEq/L + 0.964 x Competitive Reagent (Predicate: Beckman Synchron Magnesium Reagent, product 445360) |
| Range: 1.2 - 5.4 mEq/L, sY.x = 0.10 mEq/L | ||
| Detection Limit | Detection limit appropriate for clinical use. | 0.1 mEq/L (based on 30 replicate assay of diluted serum pool, SD = 0.02 mEq/L) |
| Onboard Reagent Stability | Stable for at least 8 hours. | Average changes in recovery less than 0.25 mEq/L over 8 hours. |
| Calibration Stability | Stable for at least 4 hours. | Average changes in recovery less than 0.05 mEq/L over 4 hours. |
Study Information:
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Sample sizes used for the test set and the data provenance:
- Linearity Study: n = 36 (for regression analysis of standards). The document does not specify the country of origin but implies laboratory-prepared standards.
- Precision Study: n = 60 replicates for each of the three serum samples. The control serum is commercially available, but its origin and whether the testing was prospective or retrospective are not specified.
- Method Comparison Study: n = 110 mixed serum and plasma specimens. These were collected from adult patients, implying a clinical setting. Country of origin not specified, and whether it was prospective or retrospective is not explicitly stated.
- Detection Limit Study: n = 30 replicates of a diluted serum pool.
- Stability Studies: Serum controls were assayed, but the specific number of samples or replicates for these studies is not provided beyond "average changes."
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This device is a quantitative assay for magnesium in serum and plasma, not an AI or imaging device that typically requires expert interpretation for a "ground truth" label.
- For the linearity study, the "ground truth" is the known concentration of the linearity standards.
- For the precision study, the "ground truth" is the mean concentration of the commercially available control serum.
- For the method comparison study, the "ground truth" is established by the results obtained from the legally marketed predicate device (Beckman Synchron Magnesium Reagent). No human experts are involved in establishing this "ground truth" in the context of this type of analytical method validation.
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Adjudication method for the test set:
- Not applicable. Adjudication methods like 2+1 or 3+1 are typically used in clinical trials involving subjective interpretation (e.g., radiology reads) where multiple human readers resolve disagreements. This product is an in-vitro diagnostic reagent, where results are quantitative measurements.
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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 (IVD) reagent kit, not an AI or imaging device where human readers interact with AI assistance. The study compares the new reagent's performance against a predicate device and its own analytical characteristics.
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If a standalone (i.e., algorithm-only without human-in-the-loop performance) was done:
- Yes, the studies described are standalone performance evaluations of the ATAC PAK Magnesium Reagent Kit when used with the ATAC 8000 Random Access Chemistry System. This is a chemical assay, and its performance is assessed directly through its analytical capabilities without human-in-the-loop interaction for result generation. The human "in-the-loop" would be the laboratory personnel operating the instrument and interpreting the numerical results.
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The type of ground truth used:
- Reference standards/known concentrations for linearity.
- Assigned values/agreement with the predicate device for precision and method comparison.
- Experimental observation (e.g., standard deviation of replicates) for detection limit.
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The sample size for the training set:
- Not applicable. This is a chemical reagent kit, not an AI algorithm that requires a "training set" in the machine learning sense. The "development" of the reagent would involve chemical formulation and optimization, not data training.
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How the ground truth for the training set was established:
- Not applicable, as there is no "training set" in the context of an IVD reagent.
§ 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.