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K Number
K173294
Device Name
Magnesium
Manufacturer
Abbott Laboratories
Date Cleared
2018-05-18

(214 days)

Product Code
JGJ
Regulation Number
862.1495
Type
Traditional
Panel
CH
Reference & Predicate Devices
N/A
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

The Magnesium assay is used for the quantitation of magnesium in human serum or plasma on the ARCHITECT e8000 System.

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).

Device Description

The Magnesium reagent kit contains Reagent 1 and Reagent 2. Reagent 1 contains Isocitrate dehydrogenase and D-Isocitrate potassium salt. Reagent 2 contains NADP. Both reagents contain sodium azide (0.1%) as a preservative. The assay principle is enzymatic, where magnesium acts as a cofactor in a reaction with isocitrate dehydrogenase, and the rate of increase in absorbance at 340 nm due to NADPH formation is directly proportional to magnesium concentration.

AI/ML Overview

The Abbott Laboratories Magnesium assay (LN 3P68) is intended for the quantitative determination of magnesium in human serum or plasma on the ARCHITECT c8000 System. This device is a Class I, reserved product, with product code JGJ.

Study Type: Analytical Performance Study

Acceptance Criteria and Reported Device Performance:

Acceptance CriteriaReported Device Performance
Limit of Blank (LoB): Not specified (implied to be very low)0.03 mg/dL
Limit of Detection (LoD): Not specified (implied to be very low)0.05 mg/dL
Limit of Quantitation (LoQ): Not specified (implied to be low)0.05 mg/dL
Within-Laboratory Precision:
Bio-Rad Level 1 Control1.4 %CV
Bio-Rad Level 2 Control1.0 %CV
LoQ Serum Pool - Low Mg3.4 %CV
Human Serum Pool - Normal Mg1.2 %CV
Human Serum Pool - Elevated Mg0.9 %CV
Human Serum Pool - Abnormal Mg0.8 %CV
Specimen Tube Type (Matrix Comparison): Bias from control tube across all samples of no more than ± 7.5%Range of mean difference from control tube: -4.9% to 3.8%
Interference (Various Substances): No more than ± 7.5% interference relative to targeted magnesium levelsMet criteria for all tested interferents at specified levels and targeted magnesium concentrations (2 mg/dL, 4 mg/dL, 6 mg/dL, 1.45 mg/dL, 3.490 mg/dL, 7.505 mg/dL).
Linearity: Not specified (implied to cover the measuring interval)Linear across the range of 0.26 to 12.98 mg/dL
Measuring Interval: Consistent with validated measurement range0.60 to 9.50 mg/dL
Method Comparison (Regression Slope): Not specified (implied to be close to 1)0.95
Method Comparison (Correlation Coefficient): Not specified (implied to be close to 1)0.9979
Manual Dilution: Impacted by not more than ±7.5% at specified concentrations (8, 15, and 20 mg/dL) when evaluated neat, 1:2, or 1:5 manual dilution (using 0.85% or 0.90% saline).Met criteria.

Details of the Studies:

  1. Sample Size used for the test set and the data provenance:

    • Limit of Blank, Limit of Detection, and Limit of Quantitation:
      • Test Set: LoB: 4 saline samples (zero-analyte), each tested in 10 replicates. LoD and LoQ: Minimum of 2 low-analyte level samples at each of 4 target concentrations (0.05, 0.15, 0.30, and 0.60 mg/dL), each tested in 10 replicates.
      • Data Provenance: Not explicitly stated, but likely laboratory-prepared samples. Retrospective/Prospective not specified.
    • Within-Laboratory Precision (20-Day):
      • Test Set: 6 control materials (Bio-Rad Level 1, Bio-Rad Level 2, LoQ Serum Pool, Human Serum Pool – Normal Mg, Human Serum Pool – Elevated Mg, Human Serum Pool – Abnormal Mg). Each tested in 2 replicates, 2 times per day for 20 days.
      • Data Provenance: Laboratory-prepared and commercially available controls. Human serum pools and diluted normal human serum used. Retrospective/Prospective not specified.
    • Specimen Tube Type (Matrix Comparison):
      • Test Set: Minimum of 40 sample sets for each evaluated tube type. 36 unaltered, 3 spiked, 1 diluted. These samples spanned the measuring interval (0.60 to 9.50 mg/dL).
      • Data Provenance: Fresh or frozen patient samples. Country of origin not specified. Retrospective/Prospective not specified.
    • Interference:
      • Test Set: Control and test level samples for each potential interferent. Tested in a minimum of 6 valid replicates for general interferents, 3 replicates for sulfasalazine and sulfapyridine, and a minimum of 7 replicates for copper, iron, zinc, ibuprofen, acetaminophen, salicylic acid, and triglycerides.
      • Data Provenance: Likely laboratory-prepared samples (spiked serum) and control samples. Retrospective/Prospective not specified.
    • Linearity:
      • Test Set: 3 sets of linearity standards, each with 12 levels of magnesium target concentrations (0.30 to 12.50 mg/dL). Each level tested in a minimum of 4 replicates.
      • Data Provenance: Laboratory-prepared standards using magnesium standard and 4% HSA. Retrospective/Prospective not specified.
    • Method Comparison:
      • Test Set: 122 patient serum specimens. 11 of these were normal serum samples spiked with magnesium hexachloride.
      • Data Provenance: Patient serum specimens, some spiked. One replicate of the predicate device was run at UT Southwestern Medical Center (UTSW, Dallas). Country of origin not specified, but UTSW suggests USA. Retrospective/Prospective not specified.
    • Manual Dilution:
      • Test Set: Three serum pools (human serum and magnesium chloride) at magnesium concentrations of 8, 15, and 25 mg/dL (±10%). Each pool evaluated neat, 1:2 diluted, and 1:5 diluted. Samples tested in a minimum of 7 replicates.
      • Data Provenance: Laboratory-prepared human serum pools. Retrospective/Prospective not specified.

  2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. These are analytical performance studies for an in-vitro diagnostic device measuring a chemical analyte (Magnesium), not studies requiring expert interpretation of images or clinical outcomes. The "ground truth" for these tests refers to the known concentrations or characteristics of the prepared samples or reference methods.

  3. Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable. Adjudication methods are typically used in studies involving subjective expert review (e.g., image interpretation). These are objective analytical measurements.

  4. 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 analytical performance study for an in-vitro diagnostic device, not an AI-assisted diagnostic imaging study involving human readers.

  5. If a standalone (i.e. algorithm only without human-in-the loop performance) was done: Yes, all studies described are standalone analytical performance evaluations of the device (Magnesium assay on the ARCHITECT c8000 System). There is no "human-in-the-loop" component in the measured performance of this chemical assay.

  6. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

    • Limit of Blank, Limit of Detection, and Limit of Quantitation: Gravimetrically prepared low-analyte samples and saline.
    • Within-Laboratory Precision: Commercially available control materials and laboratory-prepared human serum pools with known target concentrations.
    • Specimen Tube Type (Matrix Comparison): Comparison against results from the control tube type (serum glass tube).
    • Interference: Comparison against control samples without the interferent, with target magnesium levels.
    • Linearity: Laboratory-prepared linearity standards with known magnesium target concentrations.
    • Method Comparison: Comparison against a legally marketed predicate device (Roche Magnesium Gen.2).
    • Manual Dilution: Laboratory-prepared serum pools with known magnesium concentrations and expected dilution values.

  7. The sample size for the training set: Not applicable. This device is an in-vitro diagnostic assay for measuring magnesium, not a machine learning or AI algorithm that requires a "training set" in the conventional sense. The development of such assays involves reagent formulation and optimization, calibration, and validation, but not a distinct "training set" like in AI.

  8. How the ground truth for the training set was established: Not applicable, as there is no training set for this type of 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.