(441 days)
The Dimension Vista® Magnesium Flex® reagent cartridge (MG) method is an in vitro diagnostic test for the quantitative measurement of magnesium in human serum, plasma and urine on the Dimension Vista® 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).
The Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) is an in vitro diagnostic product for the calibration of Blood Urea Nitrogen (BUN),Calcium (CA), Cholesterol (CHOL), Creatinine (CRENCRE2), Glucose (GLU), Lactic Acid (LA), Magnesium (MG), Thyroxine (T4), Thyronine Uptake (TU) and Uric Acid (URCA) methods on the Dimension Vista® System.
CHEM 1 CAL is a liquid, frozen multi-analyte, bovine serum albumin based product used to calibrate blood urea nitrogen, calcium, cholesterol, creatinine, glucose, lactic acid, magnesium, thyroxine, thyronine uptake and uric acid. The kit consists of six vials, three vials of Calibrator A and three vials of Calibrator B.
The Dimension Vista® MG Flex® reagent cartridge uses a modified methylthymol blue (MTB) complexometric technique. MTB forms a blue complex with magnesium. Calcium interference is minimized by forming a complex between calcium and Ba-EGTA (chelating agent). The amount of MG-MTB complex formed is proportional to the magnesium concentration and is measured using a bichromatic (600 and 510 nm) endpoint technique.
The provided text describes the performance characteristics of the Dimension Vista® Magnesium Flex® reagent cartridge (MG) and the Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL). The focus is on demonstrating substantial equivalence to predicate devices and meeting established clinical laboratory guidelines. However, the information is primarily focused on analytical performance rather than clinical effectiveness or diagnostic accuracy in specific patient populations.
Here's an attempt to extract the requested information, acknowledging that some categories may not be directly applicable or fully detailed given the nature of an in vitro diagnostic device's analytical validation.
1. Table of Acceptance Criteria and Reported Device Performance
Device: Dimension Vista® Magnesium Flex® reagent cartridge (MG) for quantitative measurement of magnesium.
| Performance Characteristic | Acceptance Criteria (Implicit from CLSI Guidelines and Study Design) | Reported Device Performance (MG Assay) |
|---|---|---|
| Method Comparison (Correlation) | High correlation (e.g., r > 0.975) with a legally marketed device; slope close to 1, intercept close to 0. | Serum: Slope: 1.10, Intercept: -0.15 mg/dL, Correlation Coefficient: 1.00 (vs. Beckman AU Magnesium assay) |
| Lithium Heparin Plasma: Slope: 1.05, Intercept: -0.01 mg/dL, Correlation Coefficient: 0.994 (vs. Beckman AU Magnesium assay) | ||
| Urine: Slope: 1.05, Intercept: 0.09 mg/dL, Correlation Coefficient: 0.995 (vs. Beckman AU Magnesium assay) | ||
| Precision (Repeatability & Within-Lab CV%) | Low Coefficient of Variation (CV%) as per CLSI EP05-A2. (Specific numerical criteria are not explicitly stated, but typical ranges for clinical assays are often <10% for low concentrations and <5% for higher concentrations). | Multiqual® Unassayed Control: Level 1 (1.1 mg/dL): Repeatability 4.8%, Within-Lab 5.1%; Level 2 (2.5 mg/dL): Repeatability 2.9%, Within-Lab 2.9%; Level 3 (4.0 mg/dL): Repeatability 1.9%, Within-Lab 2.4%. |
| Serum Pool: Pool 1 (1.9 mg/dL): Repeatability 3.4%, Within-Lab 3.7%; Pool 2 (4.5 mg/dL): Repeatability 1.8%, Within-Lab 2.1%. | ||
| Liquichek™ Urine Chemistry Control: Level 1 (7.0 mg/dL): Repeatability 1.2%, Within-Lab 1.5%. | ||
| Urine Pool: Pool 1 (7.3 mg/dL): Repeatability 1.0%, Within-Lab 1.3%. | ||
| Limit of Blank (LoB) | Consistent with claimed analytical sensitivity. | Serum: 0.002 mg/dL (Claimed: 0.2 mg/dL) |
| Urine: 0.2 mg/dL (Claimed: 0.2 mg/dL) | ||
| Limit of Detection (LoD) | Consistent with claimed analytical sensitivity, with false positives and negatives <5%. | Serum: 0.1 mg/dL (Claimed: 0.3 mg/dL) |
| Urine: 0.3 mg/dL (Claimed: 0.3 mg/dL) | ||
| Limit of Quantitation (LoQ) | Total Error (TE) ≤ 0.2 mg/dL. | Serum: 0.2 mg/dL (Supports claim of 0.3 mg/dL) |
| Urine: 0.3 mg/dL (Supports claim of 0.3 mg/dL) | ||
| Linearity | High correlation coefficient (close to 1), slope close to 1, intercept close to 0 across the assay range. | Serum: Range 0.4-11.4 mg/dL, Slope: 1.0109, Intercept: -0.0089, Corr Coef: 0.9998 |
| Urine: Range 0.3-11.4 mg/dL, Slope: 0.9997, Intercept: 0.0583, Corr Coef: 0.9986 |
2. Sample Sizes Used for the Test Set and Data Provenance
- Method Comparison Study:
- Serum and Plasma: 239 samples (combined total).
- Urine: 99 samples.
- Data Provenance: Retrospective, internal testing by Siemens Healthcare Diagnostics R&D personnel. The country of origin is not specified but implicitly assumed to be the location of the Siemens R&D facility.
- Precision Testing:
- Not reported as individual patient samples. Instead, it used control materials (Multiqual QC, Liquichek Urine QC) and pooled serum/urine samples.
- Each test material was run with two test samples over 20 days, in two separate runs.
- Limit of Blank/Detection (LoB/LoD):
- Serum (LoB/LoD): 96 determinations (based on 4 blank and 4 low-level samples, tested n=5 over 3 days, using 2 reagent lots).
- Urine (LoB/LoD): 96 determinations (based on 4 blank and 4 low-level samples, tested n=5 over 3 days, using 2 reagent lots).
- Limit of Quantitation (LoQ):
- Serum: 6 serum samples, 5 replicates (n=5) of each, with 2 reagent lots, over 3 days (total of 90 replicates per lot for serum).
- Urine: 6 urine samples, 5 replicates (n=5) of each, with 2 reagent lots, over 3 days (total of 90 replicates per lot for urine). Total 180 determinations for LoQ overall.
- Linearity Testing:
- Serum: 9 prepared samples (dilutions).
- Urine: 9 prepared samples (dilutions).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The term "ground truth" typically applies to diagnostic accuracy studies where expert consensus or a gold standard (e.g., pathology) is used to classify cases. For an in vitro diagnostic device measuring an analyte concentration, the "ground truth" for the test set is established by testing the same samples using a legally marketed predicate device (Beckman AU Magnesium assay in this case) or through reference materials (e.g., NIST SRM 929 for traceability of the calibrator).
- For Method Comparison: No external experts were explicitly mentioned for interpreting results. The comparison itself uses the Beckman AU Magnesium assay as the reference.
- For Calibrator Traceability: Magnesium is traceable to NIST SRM 929 (National Institute of Standards and Technology Standard Reference Material). This implies the ground truth for calibration levels is established by a highly reputable and standardized reference.
4. Adjudication Method for the Test Set
Adjudication methods (like 2+1, 3+1) are typically used in studies involving subjective interpretation (e.g., imaging) to resolve disagreements among human readers. This concept is not directly applicable to the analytical performance studies of a quantitative in vitro diagnostic device, where results are numerical values. Discrepancies in quantitative measurements would typically be investigated through repeat testing, instrument troubleshooting, or sample re-preparation, rather than expert adjudication of an interpretation.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This type of study assesses how human readers' diagnostic performance changes with and without AI assistance. The submitted device is a quantitative in vitro diagnostic reagent cartridge and calibrator, not an AI-powered diagnostic imaging or interpretation tool designed to assist human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not relevant to this device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
While the device itself is a standalone analytical system (it measures magnesium concentrations automatically), the studies conducted are analytical performance studies, not a standalone diagnostic performance study in the sense of an algorithm interpreting clinical data to make a diagnosis without human input. The output is a quantitative measure of magnesium, which a clinician then interprets in the context of a patient's overall health.
The device itself represents "algorithm only" performance in the sense that it mechanically and biochemically performs the assay without human interpretation during the measurement process. The analytical studies (precision, linearity, LoD, etc.) demonstrate this standalone analytical performance.
7. The Type of Ground Truth Used
- For Method Comparison: The "ground truth" was established by comparison with a legally marketed predicate device, the Beckman AU Magnesium assay (K981743). This is a common approach for demonstrating substantial equivalence for in vitro diagnostics.
- For Calibrator Traceability: The ground truth for magnesium levels in the calibrator is traced to NIST SRM 929, which is a primary reference standard. This provides a highly accurate and standardized "ground truth" for the calibrator values.
- For Studies like LoB, LoD, LoQ, Linearity, Precision: The ground truth for these analytical performance characteristics is derived from statistical analysis of repeated measurements against well-defined samples (e.g., blank samples, low-level samples, serially diluted samples) and comparison to established CLSI guidelines for acceptable performance.
8. The Sample Size for the Training Set
The document does not specify a "training set" in the context of machine learning or AI algorithm development. This device is a traditional in vitro diagnostic reagent, relying on a biochemical reaction and photometric measurement, not a machine learning model that requires a discrete training phase. Therefore, the concept of a separate training set is not applicable here. The development and optimization of the reagent formulation and instrument settings would have involved extensive R&D, but this is not typically characterized as a "training set" in the AI/ML sense.
9. How the Ground Truth for the Training Set Was Established
As noted above, there is no "training set" in the AI/ML sense for this device. The physical and chemical properties of magnesium and the methylthymol blue reaction are the underlying "truth" guiding the development of the assay. Calibrator values leverage traceability to NIST SRM 929.
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
June 15, 2015
SIEMENS HEALTHCARE DIAGNOSTICS HELEN LEE REGULATORY TECHNICAL SPECIALIST 500 GBC DRIVE M/S 514 NEWARK DE 19714
Re: K140790
Trade/Device Name: Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) Dimension Vista® Magnesium Flex® Reagent Cartridge (MG) Regulation Number: 21 CFR 862.1150 Regulation Name: Calibrator, Multi-Analyte Mixture Regulatory Class: II Product Code: JIX, JGJ Dated: May 4, 2015 Received: May 5, 2015
Dear Ms. Helen Lee:
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 (OS) 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/ResourcesforYou/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,
Courtney
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) K140790
Device Name
Dimension Vista® Magnesium Flex® reagent cartridge (MG) Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL)
Indications for Use (Describe)
The Dimension Vista® Magnesium Flex® reagent cartridge (MG) method is an in vitro diagnostic test for the quantitative measurement of magnesium in human serum, plasma and urine on the Dimension Vista® 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).
The Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) is an in vitro diagnostic product for the calibration of Blood Urea Nitrogen (BUN),Calcium (CA), Cholesterol (CHOL), Creatinine (CRENCRE2), Glucose (GLU), Lactic Acid (LA), Magnesium (MG), Thyroxine (T4), Thyronine Uptake (TU) and Uric Acid (URCA) methods on the Dimension Vista® System.
| 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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5.0 510 (k) Summary
5.1 Description
Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) / Class II Dimension Vista® Magnesium Flex® reagent cartridge (MG) /Class I
This summary of 510(k) safety and effectiveness information is submitted in accordance with the requirements of SMDA 1990 and 21 CFR §807.92.
5.2 Assigned 510(k) number
The assigned 510(k) number is: K140790
5.3 Applicant and Date
| Applicant: | Helen M. LeeSiemens Healthcare Diagnostics500 GBC DriveMailstop 514Newark, DE 19714-6101 |
|---|---|
| ------------ | ---------------------------------------------------------------------------------------------------------- |
Date: June 11, 2015
5.4 Proprietary and Established Names
Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) Dimension Vista® Magnesium Flex® reagent cartridge (MG)
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5.5 Regulatory Information
Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL)
| Classification Name: | Calibrator, Multi-Analyte |
|---|---|
| Regulation Section: | 862.1150 - Calibrator |
| Classification; | Class II |
| Product Code: | JIX |
| Panel: | Clinical Chemistry |
Dimension Vista® Magnesium Flex®reagent cartridge (MG)
| Classification Name: | Photometric method, Magnesium, secondary |
|---|---|
| Regulation Section: | 862.1495 - Magnesium test system |
| Classification: | Class 1 |
| Product Code: | JGJ |
| Panel: | Clinical Chemistry |
5.6 Predicate Devices
Dimension® Chemistry 1 Calibrator (CHEM 1 CAL) - K061838 Dimension® Magnesium Flex® reagent cartridge (MG) - K061655
5.7 Device Description(s)/Test Principle:
CHEM 1 CAL is a liquid, frozen multi-analyte, bovine serum albumin based product used to calibrate blood urea nitrogen, calcium, cholesterol, creatinine, glucose, lactic acid, magnesium, thyroxine, thyronine uptake and uric acid. The kit consists of six vials, three vials of Calibrator A and three vials of Calibrator B.
The Dimension Vista® MG Flex® reagent cartridge uses a modified methylthymol blue (MTB) complexometric technique. MTB forms a blue complex with magnesium. Calcium interference is minimized by forming a complex between calcium and Ba-EGTA (chelating agent). The amount of MG-MTB complex formed is proportional to the magnesium concentration and is measured using a bichromatic (600 and 510 nm) endpoint technique.
5.8 Device Intended Use:
The CHEM 1 CAL is an in vitro diagnostic product for the calibration of Blood Urea Nitrogen (BUN) Calcium (CA), Cholesterol (CHOL), Creatinine (CREA/CRE2), Glucose (GLU), Lactic Acid (LA), Magnesium (MG), Thyroxine (T4), Thyronine Uptake (TU) and Uric Acid (URCA) methods on the Dimension Vista® System.
The MG method is an in vitro diagnostic test for the quantitative measurement of magnesium in human serum, plasma and urine on the Dimension Vista® 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).
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5.9 Indications for Use
The Dimension Vista® Chemistry 1 Calibrator (CHEM 1 CAL) is an in vitro diagnostic product for the calibration of Blood Urea Nitrogen (BUN) Calcium (CA). Cholesterol (CHOL). Creatinine (CRENCRE2), Glucose (GLU), Lactic Acid (LA), Magnesium (MG), Thyroxine (T4), Thyronine Uptake (TU) and Uric Acid (URCA) methods on the Dimension Vista® System.
The Dimension Vista® Magnesium Flex® reagent cartridge (MG) is an in vitro diagnostic test for the quantitative measurement of magnesium in human serum, plasma and urine on the Dimension Vista® 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).
5.10 Substantial Equivalence Information:
The proposed Siemens Healthcare Diagnostics Dimension Vista® CHEM 1 CAL (KC110B) and the predicate Dimension Vista® CHEM 1 CAL (K061838) are the exact same products with the same formulation. They are both in vitro diagnostics products for the calibration of Blood Urea Nitrogen, Calcium, Cholesterol, Creatinine, Glucose, Lactic Acid, Magnesium, Thyroxine, Thyronine Uptake and Uric Acid methods on the Dimension Vista® System. The modification described in this 510(k) submission is a change to use System Water instead of Dimension Vista® CHEM 1 CAL Level 1(CAL A), when calibrating the Dimension Vista® Magnesium method.
A comparison summary of the features of both products is included in the following page.
A comparison of the similarities and differences between the Dimensium Flex "reagent cartridge (MG) (proposed device) and the Dimension® Magnesium Flex reagent cartridge (MG) - K061655 is also included in the following tables.
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Similarities between the Proposed and Predicate Magnesium Devices
| Feature | Proposed Device | Predicate Device |
|---|---|---|
| Dimension Vista® MagnesiumFlex® reagent cartridge (MG) | Dimension® Magnesium Flex®reagent cartridge (MG) | |
| Intended Use | The MG method is an invitro diagnostic test for thequantitative measurement ofmagnesium in human serum,plasma and urine on theDimension Vista® System.Magnesium measurements areused in the diagnosis andtreatment of hypomagnesemia(abnormally low plasma levels ofmagnesium) andhypermagnesemia (abnormallyhigh plasma levels ofmagnesium). | The MG method usedon the Dimension® clinicalchemistry system is an invitro diagnostictest intended for thequantitative determination ofmagnesium in human serum,heparinized plasma and urine. |
Differences Between the Proposed and Predicate Magnesium Devices
| Feature | Proposed Device | Predicate Device |
|---|---|---|
| Dimension Vista® MagnesiumFlex® reagent cartridge (MG) | Dimension® Magnesium Flex®reagent cartridge (MG) | |
| Methodology | Methylthymol blue(MTB) | Methylthymol blue(MTB) |
| Calibration Interval | 90 days | 90 days |
| Limit of Blank/AnalyticalSensitivity | 0.2 mg/dL (LoB) | 0.0 mg/dL (AnalyticalSensitivity) |
| Measuring Range -Serum/Plasma | 0.3-10.0 mg/dL | 0.0-20.0 mg/dL |
| Measuring Range -Urine | 0.3-10.0 mg/dL | 0.0-20.0 mg/dL |
| Detection Conditions | Bichromatic600 and 510 nm | Bichromatic600 and 510 nm |
| Expected Values -Serum/Plasma | 1.6-2.6 mg/dL | 1.8-2.4 mg/dL |
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Similarities between the Proposed and Predicate Calibrators
| Feature | Proposed DeviceDimension Vista®CHEM 1 CAL | Predicate DeviceDimension Vista® CHEM 1 CAL(KC110B) |
|---|---|---|
| IntendedUse | Same | The CHEM 1 CAL is an in vitro diagnostic product for thecalibration of Calcium (CA), Cholesterol (CHOL), Creatinine(CREA), Glucose (GLU), Lactic Acid (LA), Magnesium (MG),Thyroxine (T4), Thyroxine Uptake (TU), Blood Urea Nitrogen(BUN) and Uric Acid (URCA) methods on the DimensionVista® System. |
| Traceability | Same | MG - NIST SRM 929 |
| Form | Same | Frozen Liquid |
Differences between the Proposed and the Predicate Calibrators
| Feature | Proposed DeviceDimension Vista® CHEM 1 CAL | Predicate DeviceDimension Vista® CHEM 1 CAL |
|---|---|---|
| Catalog # /REF | KC110B | KC110B |
| TypicalCalibration Levelsfor the MGMethod | Level 1: 0.0 mg/dL [0.00 mmol/L]will be used for Level 1 ( notCalibrator A) | Level 1 (Calibrator A): 0.3 mg/dL [0.12 mmol/L] |
| Level 2 (Calibrator B): same as thepredicate | Level 2 (Calibrator B): 21.1 mg/dL [8.68 mmol/L] |
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5.11 Standards/Guidance Document References
- Stability Testing of In Vitro Diagnostic Reagents (CEN 13640)
- . Interference Testing of Clinical Chemistry; Approved Guideline (EP07-A2)
- . Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline (EP09-A2)
- Evaluation of the Linearity of Quantitative Measurement; Approved Guideline (EP06-A) .
- Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures . (EP17-A2)
- . Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline (EP05-A2)
- . Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory: Approved Guideline Third Edition (EP28-A3c)
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Performance Characteristics 5.12
The following data represent typical method performance. Data were collected on the Dimension Vista® 1500 System.
5.12.1 Method Comparison
Testing was conducted internally by Siemens Healthcare Diagnostics R&D personnel. The technicians conducting the studies had training similar to personnel who would perform testing in a hospital laboratory setting. Technicians were trained on the operation of both the proposed device and the predicate device. A split sample method comparison study, following EP09-A2, demonstrated good agreement between the Dimension Vista® MG Flex® reagent cartridge versus the Beckman AU Magnesium assay (K981743).
A combined total of 239 serum and plasma samples were tested on the Dimension Vista® MG Flex® reagent cartridge and the Beckman AU Magnesium assay. In an additional study, 99 urine samples were tested using the Dimension Vista® MG Flex® reagent cartridge versus the Beckman AU Magnesium assay. All samples were run in duplicate however; only the first result was used for analysis.
| ComparativeMethod | SampleType | Range(mg/dL) | Slope | Intercept(mg/dL) | CorrelationCoefficient | N |
|---|---|---|---|---|---|---|
| Vista MGmethod vsBeckman AUMG method | Serum | 0.6-7.7 | 1.10 | -0.15 | 1.00 | 114 |
| Lithiumheparinplasma | 0.8-7.5 | 1.05 | -0.01 | 0.994 | 125 | |
| Urine | 1.5 - 9.3 | 1.05 | 0.09 | 0.995 | 99 |
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5.12.2 Precision
Precision testing was performed in accordance with CLSI EP05-A2 Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline- Second Edition.
Samples consisted of two serum pools, three levels of Multiqual QC material, one level of Liquichek Urine QC material and one urine pool.
Testing was performed over 20 days, two separate runs with two test samples for each test material. Analysis of variance (ANOVA) was used to evaluate the data consistent with the recommendations of EP05-A2. The following table is a summary of the data.
| Mean(mg/dL)[mmol/ dL] | Standard Deviation (%CV) | ||
|---|---|---|---|
| Repeatability | Within-Lab | ||
| Multiqual® Unassayed Control | |||
| Level 1 | 1.1 [0.45] | 0.1 [0.04] (4.8) | 0.1 [0.04] (5.1) |
| Level 2 | 2.5 [1.03] | 0.1 [0.04] (2.9) | 0.1 [0.04] (2.9) |
| Level 3 | 4.0 [1.60] | 0.1 [0.04] (1.9) | 0.1 [0.04] (2.4) |
| Serum Pool 1 | 1.9 [0.78] | 0.1 [0.04] (3.4) | 0.1 [0.04] (3.7) |
| Serum Pool 2 | 4.5 [1.85] | 0.1 [0.04] (1.8) | 0.1 [0.04] (2.1) |
| Liquichek™ Urine Chemistry Control | |||
| Level 1 | 7.0 [2.88] | 0.1 [0.04] (1.2) | 0.1 [0.04] (1.5) |
| Urine Pool 1 | 7.3 [3.00] | 0.1 [0.04] (1.0) | 0.1 [0.04] (1.3) |
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5.12.3 Limit of Blank and Limit of Detection
Serum:
The Limit of Detection (LoD) for MG, using serum samples, is 0.2 mg/dL [0.08 mmol/L], determined consistent with CLSI guideline EP17-A2 and with proportions of false positives (a) less than 5% and false negatives (ß) less than 5%; based on 96 determinations, with 4 blank and 4 low level samples.
| Dimension Vista® Magnesium Limit of Detection with Serum | ||
|---|---|---|
| Test | Protocol | Value |
| LoB | Four samples with no analyte were tested (n=5) forthree days, one run/day, using two reagent lots | 0.002 mg/dL |
| LoD | Four low serum samples were tested (n=5) forthree days one run/day, using two reagent lots | 0.1 mg/dL |
The nonparametric approach described in CLSI EP17-A2 was followed to determine the Limit of Detection.
LoB=Mean of Blank Measurement + 1.645 X Standard Deviation of Blank Measurements LoD=Limit of Blank + CpSDs
Cp is a correction factor for the 95% CI normal variate to account for bias in the SDs estimate
SDs is an estimate of imprecision pooled from replicates of the low level samples
The LoB was determined to be 0.002 mg/dL in serum samples with no analyte and is consistent with the claim of 0.2 mg/dL.
The LoD was determined to be 0.1 mg/dL in serum samples and is consistent with the claim of 0.3 mg/dL.
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Urine:
The Limit of Detection (LoD) for MG, using urine samples, is 0.3 mg/dL, determined consistent with CLSI guideline EP17-A2 and with proportions of false positives (d) less than 5% and false negatives (β) less than 5%; based on 96 determinations, with 4 blank and 4 low level samples.
| Dimension Vista® Magnesium Limit of Detection with Urine | |||
|---|---|---|---|
| Test | Protocol | Value | |
| LoB | Five diluted urine samples were tested (n=5) forthree days, one run/day, using two reagent lots | 0.2 mg/dL | |
| LoD | Five low concentration urine samples were tested(n=5) for three days one run/day, using two reagentlots | 0.3 mg/dL |
The nonparametric approach described in CLSI EP17-A2 was followed to determine the Limit of Detection.
LoB=Mean of Blank Measurement + 1.645 X Standard Deviation of Blank Measurements
LoD=Limit of Blank + CpSDs
Cp is a correction factor for the 95% CI normal variate to account for bias in the SDs estimate
SDs is an estimate of imprecision pooled from replicates of the low level samples
The LoB was determined to be 0.2 mg/dL in urine samples with no analyte and is consistent with the claim of 0.2 mq/dL.
The LoD was determined to be 0.3 mg/dL in urine samples and is consistent with the claim of 0.3 mg/dL.
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5.12.4 Limit of Quantitation
Testing involved running six serum samples and six urine samples with magnesium levels at the trial LoQ concentration of approximately 0.3 mg/dL. Five replicates (n=5) of each sample were run with two different reagent lots, on three days, to produce a total of 90 replicates for each lot. A LoQ concentration was calculated for each lot, and the larger LoQ from the 2 lots was taken as the final LoQ result.
TE = Total Error = |Bias| + 2 x sd
The calculated TE for all serum samples, for each reagent lot tested, met the goal of TE ≤ 0.2 mg/dL, therefore, the serum LoQ criterion was deemed to be met. The lowest serum sample concentration that met the goal for both reagent lots: 13361BA and 14196AA, was 0.2 mg/dL. The results support the MG LoQ claim of 0.3 mg/dL.
TE = Total Error = |Bias| + 2 x sd
The calculated TE for all urine samples, for each reagent lot tested, met the goal of TE ≤ 0.2 mg/dL, therefore, the urine LoQ criterion was deemed to be met. The lowest urine sample concentration that met the goal for both reagent lots: 14196AA and 14303BA was 0.3 mg/dL. The results support the MG LoQ claim of 0.3 mg/dL.
The LoQ for the MG assay is 0.3 mg/dL, determined consistent with the guidelines in CLSI document EP17-A2, based on 180 determinations; and a Total Error goal of 0.2 mg/dL calculated using the Westgard model.
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5.12.5 Linearity
Linearity was evaluated using a series of manually prepared dilutions of serum and urine samples that spanned the assay range. The individual samples were prepared by blending samples with high and low magnesium concentrations across the measurement range as described in CLSI Evaluation of the Linearity of Quantitative Measurement Procedures (EP06-A).
Regression Statistics
| Sample | Range | Units | Slope | Intercept | Corr Coef | n |
|---|---|---|---|---|---|---|
| Serum | 0.4 – 11.4 | mg/dL | 1.0109 | -0.0089 | 0.9998 | 9 |
| Urine | 0.3 – 11.4 | mg/dL | 0.9997 | 0.0583 | 0.9986 | 9 |
5.13 Conclusion
The Dimension Vista® Chemistry 1 Calibrator (KC110B) is substantially equivalent in design, formulation, packaging and intended use to the Dimension Vista® Chemistry 1 Calibrator previously cleared under K061838.
The modification described in this 510(k) submission is a change to use System Water instead of Dimension Vista® CHEM 1 CAL Level 1 (CAL A) when calibrating the Dimension Vista® Magnesium method. The Dimension Vista® Magnesium Flex® reagent cartridge (MG, K3057), with the truncated assay range, is substantially equivalent to the Beckman magnesium assay cleared under K981743
§ 862.1150 Calibrator.
(a)
Identification. A calibrator is a device intended for medical purposes for use in a test system to establish points of reference that are used in the determination of values in the measurement of substances in human specimens. (See also § 862.2 in this part.)(b)
Classification. Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 862.9.