(214 days)
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No
The device description and performance studies focus on a standard enzymatic assay for measuring magnesium levels, with no mention of AI or ML techniques.
No
This device is an in vitro diagnostic (IVD) assay used to quantify magnesium levels in human serum or plasma. It aids in the diagnosis and monitoring of conditions related to magnesium imbalance, but it does not directly treat or alleviate a disease or condition itself.
Yes
The "Intended Use / Indications for Use" section explicitly states that "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)." This indicates that the device aids in the diagnosis of these medical conditions.
No
The device is a reagent kit containing chemical components (Reagent 1 and Reagent 2) used in an enzymatic assay on a specific hardware system (ARCHITECT e8000 System). It is a physical diagnostic product, not software.
Yes, this device is an IVD (In Vitro Diagnostic).
Here's why:
- Intended Use: The intended use explicitly states it is "used for the quantitation of magnesium in human serum or plasma". This indicates it is used to examine specimens derived from the human body.
- Purpose: The intended use also states that the measurements are "used in the diagnosis and treatment of hypomagnesemia and hypermagnesemia". This clearly indicates a medical purpose related to diagnosing or treating a condition.
- Device Description: The device is a "reagent kit" used in an enzymatic assay to measure magnesium concentration. This is a typical description of an in vitro diagnostic reagent.
- Performance Studies: The document details various performance studies (Limit of Blank, Limit of Detection, Limit of Quantitation, Precision, Specimen Tube Type, Interference, Linearity, Measuring Interval, Method Comparison, Manual Dilution) which are standard for demonstrating the analytical performance of an IVD.
- Predicate Device: The mention of a "Predicate Device" (Roche Magnesium Gen.2) is common in regulatory submissions for IVDs, indicating a comparison to an already approved device of the same type.
All these elements align with the definition of an In Vitro Diagnostic device, which is a medical device intended for use in vitro for the examination of specimens derived from the human body solely or principally for the purpose of providing information concerning a physiological or pathological state, or concerning a congenital abnormality, or to determine the compatibility of human tissues, organs or blood, or to monitor therapeutic measures.
N/A
Intended Use / Indications for 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).
Product codes (comma separated list FDA assigned to the subject device)
JGJ
Device Description
The Magnesium reagent kit contains:
Component: 3P68-22, Number of Tests: 1000* (serum or plasma), Reagent 1 (R1): 5 × 39 mL, Reagent 2 (R2): 5 × 11 mL
Component: 3P68-32, Number of Tests: 3750* (serum or plasma), Reagent 1 (R1): 10 × 71 mL, Reagent 2 (R2): 10 × 18 mL
- Calculation is based on the minimum reagent fill volume per kit and may vary depending on the mix of serum/plasma samples.
Reagent: Reagent 1, Reactive Ingredients: Isocitrate dehydrogenase, Concentration: 2.2 U/mL
Reagent: Reagent 1, Reactive Ingredients: D-Isocitrate potassium salt, Concentration: 1.47 mg/mL
Reagent: Reagent 2, Reactive Ingredients: NADP, Concentration: 8.37 mg/mL
Inactive Ingredients: R1 and R2 contain sodium azide (0.1%) as a preservative.
Principles of the Procedure: Magnesium present in the sample is a cofactor in an enzymatic reaction with isocitrate dehydrogenase. The rate of increase in absorbance at 340 nm, due to the formation of NADPH, is directly proportional to the magnesium concentration.
Isocitrate dehydrogenase D-isocitric acid + ³ 2-oxoglutarate + CO2 + NADPH Mg2+
Methodology: Enzymatic
Mentions image processing
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Mentions AI, DNN, or ML
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Input Imaging Modality
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Anatomical Site
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Indicated Patient Age Range
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Intended User / Care Setting
Prescription Use (Part 21 CFR 801 Subpart D)
Description of the training set, sample size, data source, and annotation protocol
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Description of the test set, sample size, data source, and annotation protocol
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Summary of Performance Studies (study type, sample size, AUC, MRMC, standalone performance, key results)
Limit of Blank, Limit of Detection, and Limit of Quantitation:
The study was performed based on guidance from the Clinical and Laboratory Standards Institute (CLSI) document EP17-A2. LoB was determined using 4 obtained saline samples (zero-analyte samples). LoD and LoQ were determined using low-level analyte samples prepared from a magnesium standard. A minimum of 2 low-analyte level samples were gravimetrically prepared at each of the following 4 target concentration levels: 0.05, 0.15, 0.30, and 0.60 mg/dL. The zero-analyte samples were tested in replicates of 10. The low-analyte samples were tested in replicates of 10. Testing was performed over 3 days, two runs per day, using 2 lots of reagent, 1 lot of calibrators, and 1 lot of commercially available controls on 1 ARCHITECT c 8000 System.
The serum application of the Magnesium assay, had an LoB of 0.03 mg/dL, an LoD of 0.05 mg/dL, and an LoQ of 0.05 mg/dL.
Within-Laboratory Precision (20-Day):
Precision was evaluated using control materials and serum pools. The levels were tested in 2 replicates, 2 times per day (separated by a minimum of 2 hours) for a total of 20 testing days. Testing was performed using 1 lot of reagents, 1 lot of calibrators and 1 lot of commercially available controls on 1 ARCHITECT c 8000 System. The evaluation was performed by instrument based on guidance from CLSI document EP05-A2.
The within-laboratory imprecision (within-run, between-run, and between-day) for Magnesium serum was:
- 1.4 %CV for Bio-Rad Level 1
- 1.0 %CV for Bio-Rad Level 2
- 3.4 %CV for LoQ Serum Pool -Low Mg
- 1.2 %CV for Human Serum Pool - Normal Mg
- 0.9 %CV for Human Serum Pool Elevated Mg
- 0.8 %CV for Human Serum Pool - Abnormal Mg
Specimen Tube Type (Matrix Comparison):
The study control tube type was the serum glass tube. The following tubes types were under evaluation: serum with gel separator, sodium heparin plasma (without gel separator), lithium heparin plasma (without gel separator), and lithium heparin plasma with gel separator. Fresh or frozen sample sets were obtained that included the control tube type and at least 1 tube type under evaluation. Each tube type under evaluation was assessed using a minimum of 40 samples. The sample sets spanned the measuring interval (0.60 to 9.50 mg/dL) and included the assay's medical decision levels. Of the 40 sample sets, 36 sample sets were unaltered, three sample sets were spiked and 1 sample set was diluted.
All samples were tested in a minimum of 2 replicates using 1 lot each of reagent, Multiconstituent Calibrator (LN 1E65) and commercially available controls on 1 ARCHITECT c 8000 System. All samples collected from the same subject were tested in the same run.
The Magnesium assay, which had a mean difference from the control tube ranging from -4.9% to 3.8% met the evaluation criteria of bias from the control tube across all samples of no more than ± 7.5%. The results demonstrated that the listed blood collection tube types are acceptable for use.
Interference:
The interference study for ascorbic acid, bilirubin (conjugated), bilirubin (unconjugated), glucose, hemoglobin, Intralipid, L-dopa, and calcium was performed based on guidance from CLSI document EP07-A2. Interference effects were assessed by comparing test samples containing potentially interfering substances to control level samples. The control and test level samples were tested in a minimum of 6 valid replicates using 1 lot of reagents, 1 lot of Multiconstituent Calibrator (LN 1E65) and 1 lot commercially available controls on 1 ARCHITECT c 8000 System. The control and test level samples for a given potential interferent/magnesium level combination were tested in the same run.
Additionally, a drug interference study was performed for sulfasalazine, sulfapyridine and temozolomide.
For the copper, iron, zinc, ibuprofen, acetaminophen, salicylic acid, and triglycerides study, the control and interferent samples were tested in a minimum of 7 replicates using 1 lot of reagent, 1 lot of Multiconstituent Calibrator (LN 1E65), and 1 lot of commercially available controls on 1 ARCHITECT c8000 System. The control and interferent samples for a given potential interferent/magnesium level combination were tested in the same run.
For magnesium samples targeted to ~ 2 mg/dL, ~4 mg/dL, and ~6 mg/dL, the assay showed no more than ± 7.5% interference for the listed substances at the interferent levels indicated in the tables. Additionally, for magnesium samples targeted to ~ 1.45 mg/dL, the assay showed no more than ± 7.5% interference for sulfasalazine and sulfapyridine at concentrations up to 300 mg/L. Finally, for magnesium samples targeted to ~ 3.490 mg/dL and 7.505 mg/dL, the assay showed no more than ± 7.5% interference for temozolomide at concentrations up to 20 mg/L.
Linearity:
Linearity was determined based on guidance from Clinical and Laboratory Standards Institute (CLSI) document EP06-A. Three sets of linearity standards were prepared using a magnesium standard and 4% HSA (diluent). For each sample set, a low and high sample pool was prepared. Each sample set consisted of 12 levels. Levels 1 through 12 for each sample set were tested in a random order in a minimum of 4 replicates using 2 lots reagents and 1 lot each of Multiconstituent Calibrator (LN 1E65) and commercially available controls on 1 ARCHITECT c 8000 System. All levels in a sample set were tested in the same run.
The Magnesium assay was demonstrated to be linear across the range of 0.26 to 12.98 mg/dL, which spans the measuring interval of 0.60 to 9.50 mg/dL.
Measuring Interval:
The measuring interval was determined based on the results from 3 studies: Within Laboratory Precision (20-Day); Linearity; and Limit of Blank, Limit of Detection, and Limit of Quantitation.
The analytical measuring interval for the Magnesium assay was determined to be from 0.60 to 9.50 mg/dL.
Method Comparison:
The study was performed based on guidance from CLSI document EP09-A3. A total of 122 patient serum specimens were evaluated with the Magnesium (LN 3P68) and Roche Magnesium Gen.2 (REF 06407358 190) assays. Of these samples, 11 were normal serum samples spiked with magnesium hexachloride to achieve samples with magnesium concentrations in the range of 4.8 to 9.4 mg/dL. Three replicates were run using the Magnesium (LN 3P68) reagent kit where the first valid replicate was used in the analysis. One replicate was run at UT Southwestern Medical Center (UTSW, Dallas) using Roche Magnesium Gen.2 (REF 06407358 190) reagent. Testing was performed over 5 separate days.
The Magnesium (LN 3P68) assay, which had a regression slope of 0.95 and correlation coefficient (r-value) of 0.9979 demonstrated acceptable correlation to the predicate device.
Manual Dilution:
Three serum pools were prepared, using human serum and magnesium chloride, at magnesium concentrations of 8, 15, and 25 mg/dL (±10%). Each analyte pool was evaluated without dilution (neat) and after 1:2 and 1:5 manual dilution. Dilutions were performed using 0.85% and 0.90% (NaCl) saline. Samples were tested in a minimum of 7 replicates using 1 lot of reagent, 1 lot of Multiconstituent Calibrator (LN 1E65), and 1 lot of commercially available controls on 1 ARCHITECT c8000 System. The neat and diluted samples at a given magnesium level were tested in the same run.
Magnesium assay results were impacted by not more than ±7.5% for analyte concentrations 8, 15 and 20 mg/dL (±10%) when evaluated neat, with a 1:2, or 1:5 manual dilution (using 0.85% or 0.90% saline).
Key Metrics (Sensitivity, Specificity, PPV, NPV, etc.)
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Predicate Device(s): If the device was cleared using the 510(k) pathway, identify the Predicate Device(s) K/DEN number used to claim substantial equivalence and list them here in a comma separated list exactly as they appear in the text. List the primary predicate first in the list.
Roche Magnesium Gen.2
Reference Device(s): Identify the Reference Device(s) K/DEN number and list them here in a comma separated list exactly as they appear in the text.
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Predetermined Change Control Plan (PCCP) - All Relevant Information for the subject device only (e.g. presence / absence, what scope was granted / cleared under the PCCP, any restrictions, etc).
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§ 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.
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Image /page/0/Picture/0 description: The image contains the logos of the Department of Health and Human Services and the Food and Drug Administration (FDA). The Department of Health and Human Services logo is on the left, and the FDA logo is on the right. The FDA logo includes the letters "FDA" in a blue square, followed by the words "U.S. Food & Drug Administration" in blue text.
May 18, 2018
Abbott Laboratories Kimberly Senseman Sr. Regulatory Affairs Specialist 1921 Hurd Drive Irving, TX 75038
Re: K173294
Trade/Device Name: Magnesium Regulation Number: 21 CFR 862.1495 Regulation Name: Magnesium test system Regulatory Class: Class I. reserved Product Code: JGJ Dated: April 5, 2018 Received: April 10, 2018
Dear Kimberly Senseman:
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 Part 801 and Part 809); medical device 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
1
Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
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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Indications for Use
510(k) Number (if known) K173294
Device Name Magnesium
Indications for Use (Describe)
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).
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) |
|---|---|
| ---------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- |
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510(k) K173294 Summary (Summary of Safety and Effectiveness)
This summary of the 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.
1. Applicant Name
Kimberly Senseman, ADD, Sr. Regulatory Affairs Specialist Abbott Laboratories 1921 Hurd Drive Irving, TX 75038 (972) 518-7081 Fax: (972) 518-6854 Email: kimberly.senseman@abbott.com
Date Summary prepared: May 11, 2018
2. Device Name
Trade Name: Magnesium Device Classification: Class I Reserved Classification Name: Magnesium Reagent Governing Regulation: CFR 862.1495 Product Code: JGJ
3. Predicate Device
Roche Magnesium Gen.2
4
4. Description of Device
The Magnesium reagent kit contains:
| Component | 3P68-22 | 3P68-32 |
|---|---|---|
| Number of Tests | 1000* (serum or plasma) | 3750* (serum or plasma) |
| Reagent 1 (R1) | 5 × 39 mL | 10 × 71 mL |
| Reagent 2 (R2) | 5 × 11 mL | 10 × 18 mL |
- Calculation is based on the minimum reagent fill volume per kit and may vary depending on the mix of serum/plasma samples.
| Reagent | Reactive Ingredients | Concentration |
|---|---|---|
| Reagent 1 | Isocitrate dehydrogenase | 2.2 U/mL |
| D-Isocitrate potassium salt | 1.47 mg/mL | |
| Reagent 2 | NADP | 8.37 mg/mL |
| Inactive Ingredients: R1 and R2 contain sodium azide (0.1%) as a preservative. |
Principles of the Procedure
Magnesium present in the sample is a cofactor in an enzymatic reaction with isocitrate dehydrogenase. The rate of increase in absorbance at 340 nm, due to the formation of NADPH, is directly proportional to the magnesium concentration.
Isocitrate dehydrogenase D-isocitric acid + ³ 2-oxoglutarate + CO2 + NADPH Mg2+
Methodology: Enzymatic
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5. Intended Use of the Device
The Magnesium assay is used for the quantitation of magnesium in human serum or plasma on the ARCHITECT c 8000 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).
6. Comparison of Technological Characteristics
The Magnesium assay is used for the quantitation of magnesium in human serum or plasma on the ARCHITECT c 8000 System.
A comparison of the candidate assay (Magnesium, List No. 3P68) and the predicate assay (Roche Magnesium Gen.2 REF 06407358 190) is presented in the table on page 4.
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| Assay
Characteristics | Magnesium
LN 3P68 | Roche Magnesium Gen.2 |
|-----------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Analyte Measured | Magnesium | Same |
| Intended Use | The Magnesium assay is used for
the quantitation of magnesium in
human serum or plasma on the
ARCHITECT c 8000 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). | In vitro test for the quantitative
determination of magnesium in
human
serum, plasma and urine on
Roche/Hitachi cobas c systems. |
| Assay Principle | Magnesium present in the sample
is a cofactor in an enzymatic
reaction with isocitrate
dehydrogenase. The rate of
increase in absorbance at 340 nm,
due to the formation of NADPH,
is directly proportional to the
magnesium concentration. | Colorimetric endpoint method.
In alkaline solution, magnesium
forms a purple complex with
xylidyl blue, diazonium salt. The
magnesium concentration is
measured photometrically via
the decrease in the xylidyl blue
absorbance. |
| Detection of
Analyte | Rate-up Enzymatic | Endpoint |
| Samples | Serum, plasma | Serum, plasma or urine |
| Assay Range
- Serum/Plasma | 0.60 to 9.50 mg/dL
(0.25 to 3.90 mmol/L) | 0.243-4.86 mg/dL
(0.10-2.0 mmol/L)
1:2 Dilution:
Up to 9.72 mg/dL |
| Reference Range - Serum/Plasma | | Same |
| | Newborn, 2 to
4 days | 1.5 to 2.2 |
| | 5 months to 6
years | 1.7 to 2.3 |
| | 6 to 12 years | 1.7 to 2.1 |
| | 12 to 20 years | 1.7 to 2.2 |
| | Adult | 1.6 to 2.6 |
| Analysis Medium | Aqueous solution | Same |
| Use of Calibrators | Yes | Yes |
| Use of Controls | Yes | Yes |
| Comparison of Magnesium (LN 3P68) to Roche Magnesium Gen.2 | |
|---|---|
| ------------------------------------------------------------ | -- |
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7. Summary of Performance Testing
Limit of Blank, Limit of Detection, and Limit of Quantitation
The study was performed based on guidance from the Clinical and Laboratory Standards Institute (CLSI) document EP17-A2. LoB was determined using 4 obtained saline samples (zero-analyte samples). LoD and LoQ were determined using low-level analyte samples prepared from a magnesium standard. A minimum of 2 low-analyte level samples were gravimetrically prepared at each of the following 4 target concentration levels: 0.05, 0.15, 0.30, and 0.60 mg/dL. The zero-analyte samples were tested in replicates of 10. The low-analyte samples were tested in replicates of 10. Testing was performed over 3 days, two runs per day, using 2 lots of reagent, 1 lot of calibrators, and 1 lot of commercially available controls on 1 ARCHITECT c 8000 System.
The serum application of the Magnesium assay, had an LoB of 0.03 mg/dL, an LoD of 0.05 mg/dL, and an LoQ of 0.05 mg/dL.
Within-Laboratory Precision (20-Day)
Precision was evaluated using the following control materials.
- Level 1: Bio-Rad Lyphochek Unassayed Chemistry Control Level 1 .
- Level 2: Bio-Rad Lyphochek Unassayed Chemistry Control Level 2
- . LoQ Serum Pool -Low Mg
- Human Serum Pool Normal Mg# .
- Human Serum Pool Elevated Mg$ .
- Human Serum Pool Abnormal Mg® .
- LoQ Serum Pool - Low Mg was prepared by diluting normal human serum with normal saline to a magnesium concentration of approximately 0.6 mg/dL.
Human Serum Pool – Normal Mg is a pool of human serum specimens with a magnesium concentration ranging from 1.6 to 2.6 mg/dL.
$ Human Serum Pool - Elevated Mg and Human Serum Pool - Abnormal Mg were prepared by spiking normal human serum with a MgCl2 stock solution to a magnesium concentration of approximately 5 mg/dL and 9 mg/dL, respectively.
The levels were tested in 2 replicates, 2 times per day (separated by a minimum of 2 hours) for a total of 20 testing days. Testing was performed using 1 lot of reagents, 1 lot
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of calibrators and 1 lot of commercially available controls on 1 ARCHITECT c 8000 System.
The evaluation was performed by instrument based on guidance from CLSI document EP05-A2.
The within-laboratory imprecision (within-run, between-run, and between-day) for Magnesium serum was as follows:
- . 1.4 %CV for Bio-Rad Level 1
- 1.0 %CV for Bio-Rad Level 2 .
- . 3.4 %CV for LoQ Serum Pool -Low Mg
- . 1.2 %CV for Human Serum Pool - Normal Mg
- 0.9 %CV for Human Serum Pool Elevated Mg ●
- . 0.8 %CV for Human Serum Pool - Abnormal Mg
Specimen Tube Type (Matrix Comparison)
The study control tube type was the serum glass tube. The following tubes types were under evaluation: serum with gel separator, sodium heparin plasma (without gel separator), lithium heparin plasma (without gel separator), and lithium heparin plasma with gel separator. Fresh or frozen sample sets were obtained that included the control tube type and at least 1 tube type under evaluation. Each tube type under evaluation was assessed using a minimum of 40 samples. The sample sets spanned the measuring interval (0.60 to 9.50 mg/dL) and included the assay's medical decision levels. Of the 40 sample sets, 36 sample sets were unaltered, three sample sets were spiked and 1 sample set was diluted.
To prepare samples with elevated magnesium levels, magnesium chloride stock solution at 200 mmol/L was prepared. A total of 3 sample sets were spiked with the magnesium chloride stock solution to create sample sets each at the following magnesium levels: 5 to 6 mg/dL, 6 to 7 mg/dL and 7 to 9 mg/dL.
To prepare one sample with a magnesium concentration to be within the measuring interval, the sample was diluted with deionized water to create a sample set at 1.2 to 1.55 mg/dL.
9
All samples were tested in a minimum of 2 replicates using 1 lot each of reagent, Multiconstituent Calibrator (LN 1E65) and commercially available controls on 1 ARCHITECT c 8000 System. All samples collected from the same subject were tested in the same run. The Magnesium assay, which had a mean difference from the control tube ranging from -4.9% to 3.8% met the evaluation criteria of bias from the control tube across all samples of no more than ± 7.5%.
The results demonstrated that the following blood collection tube types are acceptable for use with the Magnesium assay: serum glass, serum with gel separator, lithium heparin, lithium heparin with gel separator, and sodium heparin.
Interference
The interference study for ascorbic acid, bilirubin (conjugated), bilirubin (unconjugated), glucose, hemoglobin, Intralipid, L-dopa, and calcium was performed based on guidance from CLSI document EP07-A2. Interference effects were assessed by comparing test samples containing potentially interfering ascorbic acid, bilirubin (conjugated), bilirubin (unconjugated), glucose, hemoglobin, Intralipid, L-dopa, and calcium samples to control level samples.
The control and test level samples were tested in a minimum of 6 valid replicates using 1 lot of reagents,1 lot of Multiconstituent Calibrator (LN 1E65) and 1 lot commercially available controls on 1 ARCHITECT c 8000 System. The control and test level samples for a given potential interferent/magnesium level combination were tested in the same run.
Additionally, a drug interference study was performed for sulfasalazine, sulfapyridine and temozolomide.
For the sulfasalazine and sulfapyridine study, solutions of each potential interferent were prepared by spiking serum with stock solutions in order to generate samples with potential interferent levels of 100 mg/L. 200 mg/L and 300 mg/L. A control sample (serum) and test level samples were tested in 3 replicates using 1 lot of reagents,1 lot of Multiconstituent Calibrator (LN 1E65) and 1 lot commercially available controls on 1 ARCHITECT c 8000 System.
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10
Lastly, a study was performed to assess the effects of copper, iron, zinc, ibuprofen, acetaminophen, salicylic acid, and triglycerides.
For the copper, iron, zinc, ibuprofen, acetaminophen, salicylic acid, and triglycerides study, the control and interferent samples were tested in a minimum of 7 replicates using 1 lot of reagent, 1 lot of Multiconstituent Calibrator (LN 1E65), and 1 lot of commercially available controls on 1 ARCHITECT c8000 System. The control and interferent samples for a given potential interferent/magnesium level combination were tested in the same run.
For magnesium samples targeted to ~ 2 mg/dL, the assay showed no more than ± 7.5% interference for the listed substances at the interferent levels indicated in the table.
| Interferent | Interferent
Level |
|--------------------------|----------------------|
| Ascorbic Acid | ≤ 3.00 mg/dL |
| Bilirubin (Conjugated) | ≤ 55.3 mg/dL |
| Bilirubin (Unconjugated) | ≤ 60.3 mg/dL |
| Glucose | ≤ 1240 mg/dL |
| Hemoglobin | ≤ 250 mg/dL |
| Intralipid | ≤ 2476 mg/dL |
| L-dopa | ≤ 5.0 mg/dL |
| Calcium | ≤ 28.0 mg/dL |
| Acetaminophen | ≤ 1592 µmol/L |
| Copper | ≤ 6.5 µg/mL |
| Iron | ≤ 641 µg/dL |
| Ibuprofen | ≤ 2915 µmol/L |
| Salicylic acid | ≤ 5.21 mmol/L |
| Triglyceride | ≤ 3647 mg/dL |
| Zinc | ≤ 4.3 µg/mL |
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For magnesium samples targeted to ~ 4 mg/dL, the assay showed no more than ± 7.5% interference for the listed substances at the interferent levels indicated in the table.
| Interferent | Interferent
Level |
|--------------------------|----------------------|
| Ascorbic Acid | ≤ 3.00 mg/dL |
| Bilirubin (Conjugated) | ≤ 55.9 mg/dL |
| Bilirubin (Unconjugated) | ≤ 60.5 mg/dL |
| Glucose | ≤ 1311 mg/dL |
| Hemoglobin | ≤ 1000 mg/dL |
| Intralipid | ≤ 2471 mg/dL |
| L-dopa | ≤ 5.0 mg/dL |
| Calcium | ≤ 28.0 mg/dL |
| Acetaminophen | ≤ 1592 µmol/L |
| Copper | ≤ 6.5 µg/mL |
| Iron | ≤ 641 µg/dL |
| Ibuprofen | ≤ 2915 µmol/L |
| Salicylic acid | ≤ 5.21 mmol/L |
| Triglyceride | ≤ 3598 mg/dL |
| Zinc | ≤ 4.3 µg/mL |
For magnesium samples targeted to ~ 6 mg/dL, the assay showed no more than ± 7.5% interference for the listed substances at the interferent levels indicated in the table.
| Interferent | Interferent
Level |
|--------------------------|----------------------|
| Ascorbic Acid | ≤ 3.00 mg/dL |
| Bilirubin (Conjugated) | ≤ 56.5 mg/dL |
| Bilirubin (Unconjugated) | ≤ 60.9 mg/dL |
| Glucose | ≤ 1199 mg/dL |
| Hemoglobin | ≤ 1200 mg/dL |
| Intralipid | ≤ 2482 mg/dL |
12
| Interferent | Interferent
Level |
|----------------|----------------------|
| L-dopa |