(108 days)
The "Wiener lab. Mg-color AA" test system is a device intended to be used in the quantitative determination of magnesium in human serum, plasma and urine. Magnesium measurement are used in the diagnosis and treatment of hypomagnesemia (abnormally low plasma levels of magnesium) and hypermagnesemia (abnormally high plasma levels of magnesium).
Magnesium, in the presence of EGTA, is coupled with xylidyl blue in an alkaline solution. Mg + Xylidyl blue -> purple complex. EGTA in the reagent complexes with calcium, so that only magnesium react with the indicator. The intensity of purple complex color formed is proportional to the magnesium concentration and can be measured photometrically.
The provided document describes the 510(k) summary for the "Mg-Color AA" device, which is a magnesium test system. The equivalence to the predicate device (ROCHE MAGNESIUM test system) is established through a comparison of their characteristics and performance.
Here's an analysis of the provided information against your requested criteria:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly state "acceptance criteria" in the traditional sense of a predetermined threshold that the device must meet to be considered effective. Instead, it presents a comparison of the Wiener lab. Mg-Color AA system's performance characteristics against those of its predicate device, the ROCHE MAGNESIUM test system, to establish substantial equivalence. The implication is that if the Wiener lab. device's performance is comparable or marginally better/worse within acceptable limits for a similar device, it is deemed acceptable.
| Performance Characteristic | ROCHE Test System (Predicate Device) Reported Performance | WIENER LAB. Mg-Color AA Test System Reported Performance | Implied Acceptance Criterion (Substantial Equivalence) |
|---|---|---|---|
| Intended Use | Quantitative determination of magnesium in human serum, plasma and urine. | Quantitative determination of magnesium in human serum, plasma and urine. | To have the same intended use. |
| Test Principle | Magnesium, in the presence of EGTA, is coupled with xylidyl blue in an alkaline solution, forming a purple complex. EGTA complexes with calcium, so only magnesium reacts. Intensity of purple complex color is proportional to magnesium concentration and measured photometrically. | Magnesium, in the presence of EGTA, is coupled with xylidyl blue in an alkaline solution, forming a purple complex. EGTA complexes with calcium, so only magnesium reacts. Intensity of purple complex color is proportional to magnesium concentration and measured photometrically. | To use the same fundamental detection chemistry/principle. |
| Essential Components | Xylidyl blue - EGTA | Xylidyl blue - EGTA | To have the same essential reactive components. |
| Reagents | R1: Buffer/EGTA, R2: Xylidyl Blue | R: Buffer/EGTA/Xylidyl Blue | Different formulation (2 reagents vs. 1 reagent), but the components are the same. Acceptance based on overall equivalent performance despite formulation difference. |
| Reagent Handling | Ready to use | Ready to use | To be a ready-to-use reagent system. |
| Instability or deterioration of reagents | Not specified | Reagent decoloration or decreased pH | To have similar stability characteristics, or to identify potential instability indicators. |
| Sample | Serum, heparinized plasma and urine | Serum, heparinized plasma and urine | To be compatible with the same sample types. |
| Working Temperature Range | Not specified | 25 - 37°C | To operate within clinically relevant temperature ranges for such assays. |
| Stability of final color | Not specified | 60 minutes | To have a stable final color for photometric measurement. |
| Wavelength range of reading | 505-600 nm | 510 - 600 nm | To read within a comparable wavelength spectrum. 5nm difference is likely acceptable. |
| Calibration | Single point | Single point | To utilize the same calibration method. |
| Linearity | 4.86 mg/dl | 6.00 mg/dl | To demonstrate comparable or improved linearity range. (Wiener lab. shows wider linearity, which is usually considered an improvement). |
| Minimum detection limit | 0.07 mg/dl | 0.08 mg/dl | To have a comparable or marginally different detection limit. (Wiener lab. is slightly higher, but likely still clinically acceptable). |
| Expected values (Serum and plasma) | 1.58-2.55 mg/dl | 1.9-2.5 mg/dl | To fall within clinically acceptable reference ranges. |
| Expected values (Urine) | 60-210 mg/24 hs (4.10-13.80 mg/dl) | 50-150 mg/24 hs (1-10 mg/dl) | To fall within clinically acceptable reference ranges. |
| Intra-assay precision | Normal Serum Control: CV = 0.8% | ||
| Abnormal Serum Control: CV = 0.7% | |||
| Human Urine 1: CV = 3.2% | |||
| Human Urine 2: CV = 0.6% | Normal Serum Control: CV = 2.0% | ||
| Abnormal Serum Control: CV = 1.9% | |||
| Human Urine 1: CV = 1.5% | |||
| Human Urine 2: CV = 1.5% | To demonstrate comparable precision (within acceptable clinical limits). For serum controls, Wiener lab. has higher CVs, for urine, it's mixed. This would be evaluated for clinical acceptability. | ||
| Inter-assay precision | Normal Serum Control: CV = 1.6% | ||
| Abnormal Serum Control: CV = 2.6% | |||
| Human Urine 1: CV = 6.3% | |||
| Human Urine 2: CV = 1.6% | Normal Serum Control: CV = 2.6% | ||
| Abnormal Serum Control: CV = 3.3% | |||
| Human Urine 1: CV = 3.1% | |||
| Human Urine 2: CV = 1.9% | To demonstrate comparable precision (within acceptable clinical limits). Wiener lab. has slightly higher CVs for serum controls and Human Urine 2, but lower for Human Urine 1. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document provides a general comparison table of characteristics and performance data but does not explicitly state the sample sizes used for the precision, linearity, or detection limit tests. It also does not specify the country of origin of the data or whether the studies were retrospective or prospective. The submitter is Wiener Laboratorios S.A.I.C. based in Rosario, Argentina.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This section is not applicable to this type of in vitro diagnostic (IVD) device. For IVDs like a magnesium test system, "ground truth" is typically established by reference methods, validated calibrators, and control materials with known concentrations, rather than expert consensus on diagnostic images. No human readers or experts are involved in establishing the "ground truth" for the test results themselves, beyond the analytical methods validating the control values.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable. See point 3.
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 device is an in vitro diagnostic (chemical reagent system) and does not involve AI, human readers, or case interpretation in the way imaging devices do.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
The device itself is a standalone chemical reagent system. Its performance (e.g., precision, linearity) is measured without human-in-the-loop performance influencing the result generation. A human operates the photometric instrument and interprets the final numerical value, but the chemical reaction and measurement are automated/standalone.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
For IVD devices like this, the "ground truth" for reported performance characteristics (e.g., precision, linearity, detection limits) would be established using:
- Certified reference materials/calibrators: For linearity and accuracy, the device's measurements are compared against samples with known, certified magnesium concentrations.
- Validated control materials: For precision, control samples with known (or tightly established) magnesium levels are repeatedly tested.
- Reference analytical methods: The results derived from the new device might be compared to a gold-standard or highly accurate reference method for magnesium measurement.
- Clinical correlation: The "expected values" are established through studies on healthy populations using validated methods.
The document implies these standard IVD validation practices by listing performance metrics, but doesn't detail the specifics of their establishment.
8. The sample size for the training set
Not applicable. This is an IVD reagent system, not an AI or machine learning device that requires a training set.
9. How the ground truth for the training set was established
Not applicable. This is an IVD reagent system, not an AI or machine learning 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.