The Randox RX daytona plus magnesium (Mg) test system is intended for the quantitative in vitro determination of magnesium concentration in serum, urine and lithium heparinized plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low levels of magnesium) and hypermagnesemia (abnormally high levels of magnesium).

Device Description

The Magnesium kit assay consists of a ready to use reagent solution.

AI/ML Overview

The document describes the analytical performance characteristics of the Randox RX daytona plus magnesium (Mg) test system, which is a quantitative in vitro diagnostic device for measuring magnesium levels in serum, urine, and lithium heparinized plasma. The study aims to demonstrate substantial equivalence to a predicate device, the Siemens Magnesium (MG) test system (K991576).

Here's a breakdown of the requested information based on the provided text:

1. A table of acceptance criteria and the reported device performance

Please note that the document does not explicitly state predetermined acceptance criteria for all performance characteristics. Instead, it often describes the methodology and then presents the results. For some sections, like Analytical Specificity, an acceptance criterion is mentioned. I will infer or state the presented performance for others.

Performance Characteristic	Acceptance Criteria (explicit or implicit)	Reported Device Performance
Precision	No explicit numerical acceptance criteria stated; inferred to be comparable to typical IVD performance for magnesium assays. The results presented should demonstrate low variability (SD, CV%).	Serum:
		QC1 (2.36 mg/dl): Total SD 0.07, CV 2.8%
		QC2 (4.36 mg/dl): Total SD 0.14, CV 3.3%
		Serum Pool 1 (0.90 mg/dl): Total SD 0.04, CV 4.1%
		Urine:
		Urine Pool 1 (3.15 mg/dl): Total SD 0.18, CV 5.8%
		LIN (21.10 mg/dl): Total SD 1.23, CV 5.8%
Linearity/Reportable Range	Deviation from linearity less than 5%. The reportable range should encompass clinically relevant magnesium levels.	Serum: Linear Regression Y = 0.96x + 0.08, r = 0.999. Reportable range: 0.74 – 4.95 mg/dl.
		Urine: Linear Regression Y = 0.97x + 0.32, r = 0.998. Reportable range: 1.01 – 23.82 mg/dl.
Detection Limit	Limit of Quantitation (LoQ) with a %CV of ≤20%. LoD and LoB also determined.	Serum: LoB 0.28 mg/dl, LoD 0.39 mg/dl, LoQ 0.55 mg/dl (with %CV ≤20%).
		Urine: LoB 0.44 mg/dl, LoD 0.68 mg/dl, LoQ 0.95 mg/dl (with %CV ≤20%).
Analytical Specificity / Interference	% of Control ± 10% for tested interferents.	Serum: No significant interference for Hemoglobin (up to 1000mg/dl), Total Bilirubin (up to 60mg/dl), Conjugate Bilirubin (up to 60mg/dl), Triglycerides (up to 2000mg/dl), Intralipid® (up to 500mg/dl), Ascorbic Acid (up to 6mg/dl) at Mg concentrations of 3.89 mg/dl and 6.32 mg/dl.
		Urine: No significant interference for various analytes at 4.87mg/dl and 24.33mg/dl Mg concentrations (e.g., Direct Bilirubin 60mg/dl, Glucose 2000mg/dl, Sodium Chloride 4000mg/dl).
Method Comparison with Predicate Device	Correlation coefficient (r) ideally close to 1.0, and regression equation (Y=mx+c) with slope (m) close to 1.0 and y-intercept (c) close to 0.0, indicating strong agreement with the predicate device.	Serum: Y = 0.994x + 0.050, r = 0.992. (Compared to Siemens Magnesium (MG) on Advia 1800).
		Urine: Y = 0.990x + 0.067, r = 0.999. (Compared to Siemens Magnesium (MG) on Advia 1800).
Matrix Comparison	Correlation coefficient (r) close to 1.0, and regression equation (Y=mx+c) for serum vs. lithium heparin plasma demonstrating equivalent results.	Y = 0.96x + 0.09, r = 0.992. (Serum vs. Lithium Heparin Plasma).

The studies described in the document, demonstrating good precision (low CVs), linearity over the stated ranges, low detection limits, minimal interference from common analytes, and strong correlation with the predicate device, collectively prove that the device meets the implicit acceptance criteria for analytical performance of a magnesium test system.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

Precision Test Set: Not explicitly stated as "test set" in the context of ground truth, but for the precision study:
- Serum: 5 different levels of unaltered human serum samples, spiked or diluted. Each level run in 80 replicates (2 replicates per run for 20 non-consecutive days, across 2 systems). So, a total of 5 levels * 80 replicates = 400 measurements for serum samples, plus control samples.
- Urine: 3 levels of human urine supplemented with magnesium chloride, plus one "LIN" sample (normal urine pool spiked). Each level run in 80 replicates. So, a total of 4 levels * 80 replicates = 320 measurements for urine samples, plus control samples.
- Data Provenance: Not explicitly stated (e.g., country of origin, retrospective or prospective). The use of "unaltered human serum samples" and "human urine supplemented with magnesium chloride" suggests real human samples, and the study design implies a prospective collection for the purpose of the study.
Linearity Test Set:
- Serum & Urine: 11 levels of samples, created by mixing low and high serum/urine pools. Each level run in 5 replicates. This means 11 levels * 5 replicates = 55 measurements per matrix (serum/urine).
- Data Provenance: Not explicitly stated. The samples were prepared from "low and high serum pools," indicating human samples were used as a base.
Detection Limit Test Set:
- Serum & Urine: 4 low-level samples for LoD/LoB/LoQ. Based on 240 determinations.
- Data Provenance: Not explicitly stated.
Analytical Specificity / Interference Test Set:
- Serum & Urine: Not specific sample sizes per interferent listed, but analytes tested at specific magnesium concentrations (e.g., 3.89 mg/dl and 6.32 mg/dl for serum; 4.87mg/dl and 24.33mg/dl for urine). Interferent levels tested are specified.
- Data Provenance: Not explicitly stated. The samples were likely prepared in-house by spiking interferents into human control matrices.
Method Comparison Test Set:
- Serum: 108 serum patient samples.
- Urine: 108 urine patient samples.
- Data Provenance: Not explicitly stated (e.g., country of origin, retrospective or prospective). These are "patient samples," which typically implies retrospective or prospectively collected clinical samples.
Matrix Comparison Test Set:
- Serum vs. Lithium Heparin Plasma: A minimum of 42 matched patient sample pairs (serum and lithium heparin plasma).
- Data Provenance: Not explicitly stated. These are "patient samples," implying clinical samples.

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 device is an in vitro diagnostic (IVD) for quantitative measurement of magnesium, not an imaging device or a device requiring human interpretation for "ground truth" in the typical sense of expert consensus. The ground truth for such devices is established through reference methods, traceability to certified reference materials, and the inherent analytical measurement of the analyte.

Reference Methods: The predicate device itself (Siemens Magnesium (MG)) serves as the "reference" for method comparison.
Traceability: The Randox Calibration Serum Level 3 is stated to be traceable to Magnesium reference material NIST 909b. This NIST standard is the ultimate "ground truth" for magnesium concentration.
No human experts are mentioned or typically involved in establishing the "ground truth" for the concentration values in these types of analytical studies. The "ground truth" is analytical, not interpretive.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. Adjudication methods like "2+1" or "3+1" are used in studies where human readers provide interpretations and discrepancies need to be resolved. This document describes analytical performance studies of a laboratory diagnostic assay, where quantitative results are compared to known concentrations or a predicate device. There is no human interpretation involved in generating the "ground truth" for the concentrations themselves, nor in interpreting the results of the device in a way that would require adjudication.

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 is an in vitro diagnostic (IVD) device for quantitative measurement of magnesium, not an AI-powered imaging device or a device requiring human readers/interpreters. Therefore, no MRMC study was conducted, and there's no concept of human readers improving with or without AI assistance for this type of device.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

This is an analytical instrument and reagent system. By its nature, its performance is "standalone" in generating a quantitative result. The device (Randox RX daytona plus system with Randox Magnesium reagents) processes samples and provides a numerical magnesium concentration. There is no "human-in-the-loop" in the sense of modifying or assisting the algorithmic output of the concentration measurement. The operator's role is to load samples and reagents and initiate the automated analysis, and then review the instrument's quantitative output.

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

The ground truth for the analytical performance studies is established by:

Reference materials/standards: Traceability to NIST 909b for calibrators, and the use of control materials with known concentrations.
Known sample preparations: For linearity and detection limit studies, samples are often prepared by spiking or diluting to known target concentrations.
Predicate device: For method comparison, the results obtained from the new device are compared to results obtained from a legally marketed predicate device (Siemens Magnesium (MG) on Advia 1800), which itself is established as accurate.

There is no expert consensus, pathology, or outcomes data used to establish the "ground truth" for magnesium concentration values in these studies.

8. The sample size for the training set

The provided document describes studies for demonstrating analytical performance and substantial equivalence to a predicate device. These are validation studies, not machine learning or AI development studies that typically involve "training sets." Therefore, the concept of a training set as understood in AI/ML is not applicable here, and no training set sample size is mentioned.

9. How the ground truth for the training set was established

As there is no "training set" in the context of AI/ML, this question is not applicable. The ground truth for the validation of the device (as discussed in point 7) is established through analytical traceability, known preparations, and comparison to an established predicate device.

Summary

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

April 28, 2017

RANDOX LABORATORIES LTD PAULINE ARMSTRONG QA/RA MANAGER 55 DIAMOND ROAD CRUMLIN BT29 4QY GB

Re: K162200

Trade/Device Name: Randox Rx Daytona Plus Magnesium (MG) Regulation Number: 21 CFR 862.1495 Regulation Name: Magnesium test system Regulatory Class: II Product Code: JGJ Dated: March 22, 2017 Received: March 24, 2017

Dear Pauline Armstrong:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate 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) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

Kellie B. Kelm -S

for Courtney H. Lias, Ph.D. Director Division of Chemistry and Toxicology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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DEPARTMENT OF HEALTH AND HUMAN SERVICESFood and Drug Administration	Form Approved: OMB No. 0910-0120Expiration Date: January 31, 2017See PRA Statement below.
Indications for Use
510(k) Number (if known)	K162200
Device Name	Randox RX daytona plus magnesium (Mg)
Indications for Use (Describe)	The Randox RX daytona plus magnesium (Mg) test system is intended for the quantitative in vitro determination of magnesium concentration in serum, urine and lithium heparinized plasma. Magnesium measurements are used in the diagnosis and treatment of hypomagnesemia (abnormally low levels of magnesium) and hypermagnesemia (abnormally high levels of magnesium).
Type of Use (Select one or both, as applicable)
Prescription Use (Part 21 CFR 801 Subpart D)	Over-The-Counter Use (21 CFR 801 Subpart C)
	CONTINUE ON A SEPARATE PAGE IF NEEDED.
	This section applies only to requirements of the Paperwork Reduction Act of 1995.
	DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
	The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
	Department of Health and Human ServicesFood and Drug AdministrationOffice of Chief Information OfficerPaperwork Reduction Act (PRA) StaffPRAStaff@fda.hhs.gov
	"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."
FORM FDA 3881 (8/14)	Page 1 of 1PSC Publishing Services (301) 443-6740

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510(K) SUMMARY, RANDOX RX DAYTONA PLUS MAGNESIUM (MG) REAGENT

1. SAFETY AND EFFECTIVENESS AS REQUIRED BY 21 CFR 807.92 STATEMENT

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

SUBMITTER NAME AND ADDRESS 2.

Name: Dr. Pauline Armstrong

Address: Randox Laboratories Limited 55 Diamond Road, Crumlin, County Antrim, BT29 4QY, United Kingdom.

Telephone: +44 (0) 28 9442 2413 Fax: +44 (0) 28 9445 2912 E-mail: Pauline.Armstrong@randox.com

Date of Summary Preparation: 28 April 2017

3. 510k NUMBER, DEVICE PROPRIETARY NAME, COMMON NAME, PURPOSE FOR SUBMISSION, REGULATORY CLASSIFCATION, PANEL, PRODUCT CODE AND 21 CFR NUMBER

510k No: K162200

Device Proprietary Name: Randox RX daytona plus magnesium (Mg)

Common Name: RX daytona plus magnesium (Mg)

Purpose for Submission: New Device

Product Code	Regulation Name	Classification	Regulation Section	Panel
JGJ	Magnesium Test System	Class I, reserved	21 CFR §862.1495 Magnesium Test System	Clinical Chemistry (75)

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4. PREDICATE DEVICE PROPRIETARY NAMES AND 510 (k) NUMBERS

Predicate Device Proprietary Name: Siemens Magnesium (MG)

510 (k) Number: K991576

5. INTENDED USE

6. DEVICE DESCRIPTION

The Magnesium kit assay consists of a ready to use reagent solution.

CATALOGUE NUMBER: MG8326

R1. Color Reagent 2 x 16.5 mL

REAGENT COMPOSITION

Contents	Initial ConcentrationsOf Solutions
R1. Colour ReagentXylidyl blueTris BufferPotassium CarbonateEGTA	0.1 mmol/L0.2 mmol/L77 mmol/L0.04 mmol/L

Materials required but not provided.

Randox Assayed Multi-sera Level 2, (Cat no. HN1530 and Level 3, HE1532, both cleared under K942458) Randox Calibration Serum Level 3, (Cat no. CAL2351, cleared under K053153) RX series Saline (Cat. No. SA8396) RX series Acid Wash Solution (Cat. No. WS8397)

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7. PREDICATE DEVICE COMPARISON TABLE

Table 1 Comparison of Randox RX daytona plus magnesium (Mg) to the

predicate device

Characteristics	Randox RX daytona plus magnesium(Mg)(Candidate Device)	Siemens Magnesium (MG)(Predicate Device)
Intended Use	The Randox RX daytona plusmagnesium (Mg) test system is intendedfor the quantitative in vitro determinationof magnesium concentration in serum,urine and lithium heparinized plasma.Magnesium measurements are used inthe diagnosis and treatment ofhypomagnesemia (abnormally low levelsof magnesium) and hypermagnesemia(abnormally high levels of magnesium)	For the quantitative in vitrodetermination of magnesiumconcentration in human plasma, serumand urine on ADVIA Chemistrysystems
Assay Protocol	Colorimetric Method	Same
Test Principle	Magnesium ions react with xylidyl blue inan alkaline medium to form a watersoluble purple-red chelate, the colourintensity of which is proportional to theconcentration of magnesium in thesample. Calcium is excluded from thereaction by complexing with EGTA.	Same
Sample Type	Serum, urine andlithium heparinized plasma	Same
Storage(Unopened)	Reagents are stable up to the expiry datewhen stored unopened at +2 to +8°C	Same
Control Frequency	Randox Assayed Multi-sera, Level 2 andLevel 3 are recommended for dailyquality control. Two levels of controlsshould be assayed at least once a day.	Siemens recommends the use ofcommercially available quality controlmaterials with at least 2 levels (low andhigh). Analyse at least 2 levels ofcontrols daily.
Calibration	0.9% NaCl solution and RandoxCalibration Sera Level 3 arerecommended for calibration.	Siemens Chemistry CalibratorREF 09784096 (T03-1291-62)
ReagentComposition	R1. Colour ReagentXylidyl blue 0.1 mmol/LTris Buffer 0.2 mmol/LPotassium Carbonate 77 mmol/LEGTA 0.04 mmol/L	Reagent 1Tris buffer 500 mmol/LSodium azide 0.09%Reagent 2Xylidyl blue 0.28 mmol/LSodium azide 0.09%
Measuring Range	Serum 0.74 – 4.95 mg/dlUrine 1.01 – 23.82 mg/dl	Serum 0.7 - 5.0 mg/dlUrine 0.5 - 25.0 mg/dl

TEST PRINCIPLE (1-5)

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Magnesium ions react with xylidyl blue in an alkaline medium to form a water soluble purple-red chelate, the colour intensity of which is proportional to the concentration of magnesium in the sample. Calcium is excluded from the reaction by complexing with EGTA.

1. Mann, C.K., Yoe, J.H., Anal. Chem. 1956, 28: 202-205.
1. Mann, C.K., Yoe, J.H., Anal. Chim. Acta (1957), 16: 155-160.
1. Ogata, H., Hiroi, L., Anal. Chem. (1959), 8: 21.
1. Bohuon, C., Clin. Chim. Acta. (1962), 7: 811-817.
1. Rice E.N., Lapara, C.Z., Clin. Chim. Acta. (1964) 10: 369.

9. PERFORMANCE CHARACTERISTICS

Analytical performance:

a. Precision/Reproducibility:

Precision was evaluated consistent with C.L.S.I documents EP05-A3 'Evaluation of Precision of Quantitative Measurement Procedures: Approved Guideline- Third Edition'. Precision studies were performed by two operators on two RX daytona plus systems using control material.

For serum precision study unaltered human serum samples that were spiked with magnesium chloride or diluted producing five different levels ranging from 0.90-4.43 ma/dl.

Urine precision study used three levels of human urine supplemented with magnesium chloride. The three levels used ranged from 3.15-12.42 mg/dl. In addition the 'LIN' sample used consisted of a normal urine pool spiked up to an elevated level of 21.10 mg/dl using magnesium chloride.

Testing was conducted for two reagent lots of Magnesium, one lot on each RX daytona plus system, twice per day for 20 non-consecutive days. Two replicates per run were performed for each sample. The assay was calibrated on the first day of the study and no assay re-calibrations were required throughout the duration of the study. The results of Serum Lot 2 and Urine lot 1, which are representative of both lots of reagent, are summarized in the following table.

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Serum Lot 2			Mean	Within Run		Total
Method	Product	N	(mg/dl)	SD	CV	SD	CV
Magnesium	QC1 (Control 2, lot 1093UN)	80	2.36	0.06	2.4	0.07	2.8
Magnesium	QC2 (Calibrator, lot 844UE)	80	4.36	0.12	2.7	0.14	3.3
Magnesium	QC3 (Control 3, lot 845 UE)	80	4.23	0.12	2.8	0.12	2.8
Magnesium	Serum Pool 1	80	0.90	0.02	2.3	0.04	4.1
Magnesium	Serum Pool 2	80	1.17	0.03	3.0	0.05	4.1
Magnesium	Serum Pool 3	80	2.54	0.04	1.8	0.07	2.8
Magnesium	Serum Pool 4	80	3.64	0.06	1.7	0.10	2.8
Magnesium	Serum Pool 5	80	4.43	0.06	1.4	0.10	2.3

Table 3: Precision Summary- Urine Lot 1

Urine Lot 1			Mean	Within Run		Total
Method	Product	N	(mg/dl)	SD	CV	SD	CV
Magnesium	QC1	80	4.58	0.13	2.9	0.23	5.1
Magnesium	QC2	80	7.68	0.20	2.6	0.32	4.2
Magnesium	Urine Pool 1	80	3.15	0.10	3.3	0.18	5.8
Magnesium	Urine Pool 2	80	9.05	0.19	2.1	0.42	4.7
Magnesium	Urine Pool 3	80	12.42	0.23	1.8	0.73	5.9
Magnesium	LIN	80	21.10	0.27	1.3	1.23	5.8

b. Linearity/assay reportable range:

Linearity studies have been carried out in accordance with C.L.S.I. standard EP6-A- 'Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach; Approved Guideline'. Linearity studies were performed at 11 levels to determine the analytical range of an assay - that is the range where the reported result is a linear function to the analyte concentration (or where deviation from linearity is less than 5%).

The linearity samples were prepared at 11 levels. The sponsor set a range for analyte concentration from approximately 0.70 mg/dl (serum) and 0.95 mg/dl (urine) up to high concentrations of approximately 5 mg/dl (serum) and 25 mg/dl (urine) using low and high serum pools. The low and high pools were mixed to make nine intermediate levels. Each level was run in replicates of five on two lots of Magnesium reagent on one RX daytona plus system. The observed values were compared to the expected values; the linear regression correlation between the expected values and the observed values are summarized in the following table:

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Table 4: Linearity Summary including Regression equation and correlation co-efficient.

Analyte Tested	Magnesium (mg/dl)(Serum)
Linear Regression	$Y = 0.96x+0.08$
r	0.999

Analyte Tested	Magnesium (mg/dl)(Urine)
Linear Regression	Y=0.97x+0.32
r	0.998

The reportable range of the assay is 0.74-4.95 mg/dl in serum and 1.01-23.82 mq/dl in urine.

The low end of the range is based on the LOQ and the high end of the reportable assay range is based on the linearity.

c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Refer to K053153 Randox Calibration Serum Level 3 and K942458 Randox Assayed Multi-sera Level 2 and Level 3.

The Randox Calibration Serum Level 3 is traceable to Magnesium reference material NIST 909b.

d. Detection limit:

Sensitivity studies have been carried out in accordance with C.L.S.I. guideline EP17-A2- 'Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures; Approved Guideline - - Second Edition'. A Limit of Blank (L.o.B), a Limit of Detection (L.o.D) and a Limit of Quantification (L.o.Q) were performed on two lots of reagents tested by two operators on one RX daytona plus system. The results of lot 1 for both serum and urine, which are representative of both lots, are summarized below.

The Limit of Detection (LoD) for magnesium on the RX daytona plus is 0.39 mg/dl for serum and 0.68mg/dl for urine, based on 240 determinations, with 4 low level samples.

The Limit of Blank (LoB) is 0.28 mg/dl for serum and 0.44 mg/dl for urine.

The Limit of Quantitation (LoQ) is 0.55mg/dl for serum and 0.95mg/dl for urine, as determined by the lowest concentration detected with a %CV of ≤20%.

Confidential

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e. Analytical Specificity:

Interference studies have been carried out in accordance with C.L.S.I. quideline EP07-A2- 'Interference Testing in Clinical Chemistry; Approved Guideline -Second Edition'. The effects of potential interferents were determined by calculating the mean value of the spiked interferent with the corresponding control solution. The spiked sample results were compared to control samples prepared without the potential interferents.

Acceptance Criteria: % of Control ± 10%

Serum Interference

The following analytes were tested up to the levels indicated at magnesium concentrations of 3.89 mg/dl and 6.32 mg/dl and found not to interfere:

Hemoglobin	No significant interference up to 1000mg/dl.
Total Bilirubin	No significant interference up to 60mg/dl.
Conjugate Bilirubin	No significant interference up to 60mg/dl.
Triglycerides	No significant interference up to 2000mg/dl.
Intralipid®	No significant interference up to 500mg/dl.
Ascorbic Acid	No significant interference up to 6mg/dl.

Urine Interference

The following analytes were tested up to the levels indicated at magnesium concentrations of 4.87mg/dl and 24.33mg/dl and found not to interfere:

	4.87mg/dl	24.33mg/dl
Direct Bilirubin	60mg/dl	60mg/dl
Total Bilirubin	60mg/dl	60mg/dl
Haemoglobin	250mg/dl	250mg/dl
G-Globulin	500mg/dl	500mg/dl
Glucose	2000mg/dl	2000mg/dl
Ascorbic Acid	150mg/dl	200mg/dl
H.S.A	500mg/dl	500mg/dl
Oxalate	100mg/dl	100mg/dl
Ethanol	1000mg/dl	1000mg/dl
Boric Acid	750mg/dl	1000mg/dl
Sodium Chloride	4000mg/dl	4000mg/dl
Sodium Fluoride	25mg/dl	25mg/dl

f. Method comparison with predicate device:

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Correlation studies were carried out in accordance with C.L.S.I. quideline EP09-A3- 'Measurement Procedure Comparison and Bias Estimation Using Patient Samples; Approved Guideline - Third Edition'. 108 serum patient samples spanning the range 0.80-4.54 mg/dl were tested by two operators on two lots of Randox RX daytona plus magnesium (Mq) reagent on one RX daytona plus analyzer and on two lots of Siemens Magnesium (MG) reagent on one Advia 1800 system across 3 working days with each sample tested in singlicate. The test method was compared to the predicate device and the following linear regression equation was obtained:

Y = 0.994x+0.050 Correlation coefficient of r = 0.992

108 urine patient samples spanning the range 1.15 to 23.12 mg/dL were tested by two operators on two lots of Randox RX daytona plus magnesium (Mg) reagent on one RX daytona plus analyzer and two lots of Siemens Magnesium (MG) reagent on one Advia 1800 sytem across three working days with each sample being tested in singlicate. The test method was compared to the predicate device and the following linear regression equation was obtained:

Y = 0.990x +0.067 Correlation coefficient of r = 0.999

q. Matrix comparison:

Matrix method comparisons for the Randox RX daytona plus magnesium (Mg) assay were tested by one operator on one RX daytona plus system and were assessed for two lots of magnesium reagents. Both serum and lithium heparin plasma were tested to determine whether method accuracy with plasma specimens are equivalent to serum results and that lithium heparin plasma does not interfere with either the method or the system.

Magnesium matrix comparison on the RX daytona plus (Lithium Heparin)

Patient samples were drawn in matched pairs - one sample serum (x) and the second sample lithium heparin plasma (y). A minimum of 42 matched patient sample pairs were analyzed spanning the range 0.75 to 4.13 mg/dl and the following linear regression equation was obtained:

Y = 0.96x+0.09 Correlation coefficient of r = 0.992

Expected values/Reference range:

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Image /page/11/Picture/0 description: The image shows the word "RANDOX" in a bold, sans-serif font. The letters are a dark green color, except for the "O", which is a red circle with a white ring around it. The word is horizontally oriented and centered.

Referenced from literature

Table 5: Reference Ranges

Analyte	Serum	Urine (24hr)
Magnesium (6,7)	Adult 1.70 - 2.70 mg/dL	Adult 72.9-121.5 mg/day

Lau, K-K., Yu, W-C., Chu, C-M., Lau, S-T., Sheng, B. and Yuen, K-Y. Possible Central Nervous System Infection by SARS Caronavirus. Emerging Infectious Diseases. Vol 10 No 2. (2004) p342-344.
Wu AH. Tietz Clinical Guide to Laboratory Tests, 4th ed. Philadelphia, PA: WB Saunders; 2006: 706-8

10. CONCLUSION

Testing results indicate that the proposed device is substantially equivalent to the predicate device.

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.