The Magnesium assay is used for the quantitation of magnesium in human serum, plasma, or urine. 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).

Device Description

Magnesium is an in vitro diagnostic assay for the quantitative determination of magnesium in human serum, plasma, or urine. The Magnesium assay is a clinical chemistry assay which utilizes an arsenazo dye which binds preferentially with magnesium. The absorbance of the arsenazo magnesium complex is measured at 550 nm and is proportional to the concentration of magnesium present in the sample. Calcium interference is prevented by incorporation of a calcium chelating agent.

AI/ML Overview

Here's a summary of the acceptance criteria and the study details for the K981791 (Magnesium assay) device, based on the provided text:

Acceptance Criteria and Device Performance

The provided document describes a "substantial equivalence" study, where the new device (Abbott Laboratories Magnesium assay) is compared to a legally marketed predicate device (Boehringer Mannheim® Magnesium assay) to demonstrate similar performance characteristics. The acceptance criteria are implicitly defined by achieving "acceptable correlation" and displaying similar performance to the predicate device.

Table of Acceptance Criteria and Reported Device Performance

Performance Characteristic	Acceptance Criteria (Implicit - demonstrating substantial equivalence to predicate)	Reported Device Performance (Abbott Magnesium Assay)
Serum Application:
Correlation Coefficient	Acceptable correlation to Boehringer Mannheim Magnesium assay	0.9884
Slope	Acceptable correlation to Boehringer Mannheim Magnesium assay	0.961
Y-intercept	Acceptable correlation to Boehringer Mannheim Magnesium assay	0.134 mEq/L
Total %CV (Level 1)	Acceptable precision	4.4%
Total %CV (Level 2)	Acceptable precision	3.4%
Linearity	Comparable to predicate, or within clinically acceptable range	Up to 7.79 mEq/L
Limit of Quantitation	Comparable to predicate, or clinically acceptable sensitivity	0.38 mEq/L
Urine Application:
Correlation Coefficient	Acceptable correlation to Boehringer Mannheim Magnesium assay	0.9866
Slope	Acceptable correlation to Boehringer Mannheim Magnesium assay	1.068
Y-intercept	Acceptable correlation to Boehringer Mannheim Magnesium assay	-0.222 mEq/L
Total %CV (Level 1)	Acceptable precision	4.5%
Total %CV (Level 2)	Acceptable precision	2.9%
Linearity	Comparable to predicate, or within clinically acceptable range	Up to 21.7 mEq/L
Limit of Quantitation	Comparable to predicate, or clinically acceptable sensitivity	(Not explicitly stated for urine, assumed to be same or similar to serum)

Note on Acceptance Criteria: For a 510(k) submission, "substantial equivalence" is the primary acceptance criterion. This means the device performs as safely and effectively as a legally marketed predicate device. The specific numerical targets for correlation, slope, intercept, and CVs are not explicitly stated as "acceptance criteria" but are reported as the results that demonstrate this substantial equivalence. They are implicitly acceptable because the conclusion states the assay "yielded acceptable correlation" and the overall performance is "substantially equivalent."

Study Details

Sample Size used for the test set and the data provenance:
- Sample Size for Test Set: Not explicitly stated for either the serum or urine method comparison. The document mentions "comparative performance studies" and "precision studies... using two levels of control material." The number of patient samples used for the method comparison is not provided.
- Data Provenance: Not explicitly stated (e.g., country of origin). The study involved "human serum, plasma, or urine." It is retrospective since it involved collecting samples and testing them against a predicate.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- This is an in vitro diagnostic assay for a quantitative measurement of magnesium. The ground truth for such devices is typically established through a reference method or comparison to an established, validated method (the predicate device in this case), rather than expert clinical consensus or interpretation of complex images. Therefore, the concept of "experts" establishing ground truth in the traditional sense (e.g., radiologists) does not apply here. The "ground truth" is essentially defined by the predicate device's performance.
Adjudication method for the test set:
- Not applicable as this is a quantitative chemical assay, not an interpretive diagnostic device requiring adjudication of ambiguous results by experts.
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 a standalone in vitro diagnostic assay. It does not involve human readers interpreting results with or without AI assistance.
If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- Yes, this is a standalone device. The performance characteristics (correlation, precision, linearity, sensitivity) are reported for the assay itself (algorithm/methodology) without human intervention in the result determination process. The results are quantitative values rather than human-interpreted outputs.
The type of ground truth used:
- Predicate Device Comparison: The ground truth for establishing substantial equivalence was the performance of the Boehringer Mannheim® Magnesium assay (K811194) on the Hitachi® 717 Analyzer. This established, legally marketed device serves as the reference against which the new device's performance is compared for accuracy and similarity. The precision, linearity, and sensitivity are intrinsic performance characteristics of the assay itself, evaluated against defined analytical standards.
The sample size for the training set:
- Not applicable. This is an in vitro diagnostic assay, not an AI or machine learning model that requires a distinct "training set." The methodology (utilizing an arsenazo dye) is based on established chemical principles.
How the ground truth for the training set was established:
- Not applicable, as there is no "training set" in the context of this chemical assay.

Summary

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K981791

510(k) Summary

OCT 2 3 1998

Submitter's Name/Address Abbott Laboratories 1920 Hurd Drive Irving, Texas 75038

Contact Person Mark Littlefield Section Manager MS 1-8 Regulatory Affairs (972) 518-6062 Fax (972) 753-3367

Date of Preparation of this Summary:	May 20, 1998
Device Trade or Proprietary Name:	Mg
Device Common/Usual Name or Classification Name:	Magnesium
Classification Number/Class:	75JGJ/Class I

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is:

Test Description:

Substantial Equivalence:

The Magnesium assay is substantially equivalent to the Boehringer Mannheim® Magnesium assay (K811194) on the Hitachi® 717 Analyzer for both the serum and the urine applications.

Magnesium 510(k) May 20, 1998 Magf.lwp

Section II Page 1

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These assays yield similar Performance Characteristics.

Similarities:

. Both assavs are in vitro clinical chemistry methods.
. Both assays can be used for the quantitative determination of magnesium.
Both assays yield similar clinical results. o

Differences:

There is a minor difference between the serum assay ranges. .

Intended Use:

The Magnesium assay is used for the quantitation of magnesium in human serum, plasma, or urine.

Performance Characteristics:

Comparative performance studies were conducted using the AEROSET™ System. The Magnesium assay method comparison yielded acceptable correlation with the Boehringer Mannheim Magnesium assay on the Hitachi 717 Analyzer for both the serum and the urine applications. For the serum application, the correlation coefficient = 0.9884, slope = 0.961 and the Y-intercept = 0.134 mEq/L. For the urine application, the correlation coefficient = 0.9866, slope = 1.068 and the Y-intercept = -0.222 mEq/L. Precision studies were conducted using the Magnesium assay. Within-run. between-run, and between-day studies were performed using two levels of control material. For the serum application, the total %CV for Level 1/Panel 101 is 4.4% and Level 2/Panel 102 is 3.4%. For the urine application, the total %CV for Level 1/Panel 201 is 4.5% and Level 2/Panel 202 is 2.9%. The Magnesium assay is linear up to 7.79 mEq/L for the serum application, and 21.7 mEq/L for the urine application. The limit of quantitation (sensitivity) of the Magnesium assay is 0.38 mEq/L. These data demonstrate that the performance of the Magnesium assay is substantially equivalent to the performance of the Boehringer Mannheim Magnesium assay on the Hitachi 717 Analyzer for both serum and urine applications.

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Conclusion:

The Magnesium assay is substantially equivalent to the Boehringer Mannheim Magnesium assay on the Hitatchi 717 Analyzer for the serum and urine applications as demonstrated by results obtained in the studies.

Magnesium 510(k) May 20, 1998
Magf.lwp

Section II Page 3

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Food and Drug Administration 2098 Gaither Road Rockville MD 20850

OCT 2 3 1998

Mark Littlefield Section Manager, Regulatory Affairs Abbott Laboratories 1920 Hurd Drive Irving, Texas 75038

K981791 Re : Maqnesium Requlatory Class: I Product Code: JGJ Dated: October 13, 1998 Received: October 13, 1998

Dear Mr. Littlefield:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions The general controls provisions of the Act of the Act. include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major requlations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical General regulation (21 CFR Part 820) and that, Devices: through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.

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Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770) 488-7655.

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to
premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".

sincerely yours,
Steven Bitman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

Device Name: _________________________________________________________________________________________________________________________________________________________________

Indications For Use:

(Division Sign-Off)
Division of Clinical Laboratory Devices
510(k) Number	KC981791

(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use	✓
(Per 21 CFR 801.109)	OR
	Over-The-Counter Use ______

(Optional Format 1-2-96)

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Regulation Number and Section

§ 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.