(186 days)
The PLAC® Test for Lp-PLA2 Activity is an enzyme assay for the in vitro quantitative determination of Lp-PLA2 (lipoprotein-associated phospholipase A2) activity in EDTA-plasma and serum on automated clinical chemistry analyzers. Lp-PLA2 activity is to be used in conjunction with clinical evaluation and patient risk assessment as an aid in predicting risk of coronary heart disease (CHD) in patients with no prior history of cardiovascular events.
The Lp-PLA2 Activity Test Calibrators are intended to establish points of reference that are used in the determination of values in the measurement of Lp-PLA2 activity by the PLAC® Test for Lp-PLA2 Activity.
The Lp-PLA2 Activity Test Controls are intended for use as a quality control tool to monitor the performance within the clinical range of the PLAC® Test for Lp-PLA2 Activity, an enzyme assay for the quantitative determination of Lp-PLA2 activity.
The PLAC® Test for Lp-PLA2 Activity consists of the reagents, Lp-PLA2 Activity Test Calibrators and Lp-PLA2 Activity Test Controls for the measurement of Lp-PLA2 activity in EDTA-plasma or serum on automated clinical laboratory analyzers.
Lp-PLA2, in plasma or serum, hydrolyzes the sn-2 position of the substrate, 1myristoyl-2-(4-nitrophenylsuccinyl) phosphatidylcholine, producing a colored reaction product, 4-nitrophenol. The rate of formation of 4-nitrophenol is measured spectrophotometrically for 8.5 minutes and the Lp-PLA2 activity is calculated from the rate of change in absorbance. A set of five Lp-PLA2 calibrators is used to generate a standard curve fit of change in absorbance versus Lp-PLA2 activity level in nmol/min/mL from which the sample Lp-PLA2 activity is derived.
The PLAC® Test for Lp-PLA2 Activity also includes controls. Controls should be included in each run or in accordance with the user's laboratory's quality control policies.
Here's an analysis of the provided text regarding the acceptance criteria and study for the PLAC® Test for Lp-PLA2 Activity:
The document primarily focuses on non-clinical performance testing to demonstrate substantial equivalence to a predicate device. There is limited information on clinical acceptance criteria against specific clinical endpoints derived from a prospective study. The "acceptance criteria" presented are primarily for analytical performance metrics.
1. Table of Acceptance Criteria and Reported Device Performance
Note: The document provides analytical performance criteria rather than clinical effectiveness criteria. The "Acceptance Criteria" column below is extracted directly from the precision tables or implied by the statements for other analytical metrics.
| Performance Metric | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Precision (Total CV) | ≤8% | Lot 1: Kit Control Low (2.6%), Kit Control High (2.2%), Sample 1 (2.0%), Sample 2 (2.0%), Sample 3 (2.4%), Sample 4 (1.5%) Lot 2: Kit Control Low (2.3%), Kit Control High (2.3%), Sample 1 (2.1%), Sample 2 (2.7%), Sample 3 (2.9%), Sample 4 (2.1%) Lot 3 (partial data): Kit Control High (2.3%), Sample 1 (2.2%), Sample 2 (2.2%), Sample 3 (2.4%), Sample 4 (2.1%) All reported total CVs are < 3%. |
| Precision (Within-Run CV) | ≤5% | All reported within-run CVs are between 1.0% and 1.9%. |
| Analytical Sensitivity | LoQ: ≤ 20% CV (at 10 nmol/min/mL) | LoB: 0.40 nmol/min/mL LoD: 0.74 nmol/min/mL LoQ: 10 nmol/min/mL (with allowable CV of 20%) |
| Linearity | Deviation from linearity ≤10% | Slopes: 0.98 to 1.04 Intercepts: -0.4 to -0.03 nmol/min/mL R² values: 0.995 to 0.999 Linearity demonstrated from 10 to 382 nmol/min/mL with deviation from linearity ≤10%. |
| Recovery | Undefined explicit criteria; implied good correlation | Slopes: 0.99 to 1.10 Intercepts: -2.9 to 4.2 nmol/min/mL R² values: 0.997 to 1.000 |
| Endogenous Interferences | 90-110% recovery in measured Lp-PLA2 activity level | All tested substances (Albumin, Conjugated Bilirubin, Unconjugated Bilirubin, Cholesterol, Triglycerides, Hemoglobin) met the 90-110% recovery criterion at specified high concentrations. |
| Exogenous Interferences | "No appreciable interference" | No appreciable interference observed for all listed substances (Acetaminophen, Aspirin, Atorvastatin, Diphenhydramine, Fenofibrate, Lisinopril, Niacin, Tolbutamide, Warfarin, Metformin, Clopidogrel bisulfate, Vitamin C) at tested low and high concentrations. |
| Specimen Stability | (Reference to package insert) | Whole blood: Up to 4 hours at 20-22°C or up to 30 hours at 2-8°C After centrifugation: 24 hours at 20-26°C Up to 2 weeks at 2-8°C Up to 18 months at -20°C Up to 2 years at -70°C Freeze/thaw: Up to 5 times at -70°C or -20°C Transport: on cold packs at 2-8°C |
| Reagent Stability | (Reference to package insert) | Shelf life: 12 months at 2-8°C (demonstrated 13 months real-time) Opened vial: 4 weeks at 2-8°C (reagents); 3 months at 2-8°C (calibrators/controls) (established 16-weeks for opened vials) On-board: 4 weeks at 2-8°C (established 6-weeks) |
| Matrix Comparison | "Comparable to K2 EDTA plasma" | All tested tube types (K3 EDTA plasma without separator gel, K2 EDTA plasma and serum with and without separator gel) were comparable to K2 EDTA plasma tube without separator gel. |
2. Sample Size Used for the Test Set and Data Provenance
- Precision: 4 native plasma samples, 2 kit controls (low and high) were tested. Each sample/control was tested with 2 replicates per run, 2 runs per day for 20 days (N=80 results for each sample/control).
- Analytical Sensitivity (LoB, LoD, LoQ): Not specified beyond "performed according to CLSI EP17-A2."
- Linearity: "Several dilution series were prepared from native plasma samples." Specific number not given.
- Recovery: "Seven activity levels" were created, but the number of unique samples is not given.
- Endogenous Interferences: Four plasma samples with varying Lp-PLA2 levels were used. Five replicates were tested for each level.
- Exogenous Substances: Four native plasma samples were used. Each spiked potential interferent was tested in duplicate.
- Matrix Comparison: Five different blood collection tube matrices were compared with an unspecified number of samples (Lp-PLA2 activity values ranged from 56 to 357 nmol/min/mL).
Data Provenance: The document does not explicitly state the country of origin for the samples used in these non-clinical studies. The studies are retrospective in the sense that they are laboratory evaluations of device performance characteristics (analytical validation) using collected samples, rather than prospective clinical trials.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This information is not applicable to the provided document, as the studies described are analytical performance evaluations of an in vitro diagnostic (IVD) device. The "ground truth" for these tests refers to the known concentrations or activity levels of the analyte (Lp-PLA2) in the samples, or the expected chemical behavior, established through reference methods or spiking, not through expert clinical image interpretation or diagnosis.
4. Adjudication Method for the Test Set
This information is not applicable. Adjudication methods (like 2+1, 3+1) are typically used in clinical studies where multiple readers assess cases and a consensus or tie-breaking mechanism is needed for the ground truth. The studies described here are laboratory analytical performance validations, not involving human readers or case adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. The document does not describe any study involving human readers or cognitive tasks where AI assistance could improve performance. This device is an in vitro diagnostic (IVD) for laboratory use.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The studies described are for a standalone IVD device, meaning the algorithm/assay performance is evaluated inherently without human-in-the-loop performance in the context of the assay's function. The "algorithm" here is the enzyme assay itself and the calculation of Lp-PLA2 activity from absorbance changes.
7. The Type of Ground Truth Used
For the analytical performance studies, the "ground truth" was established based on:
- Known concentrations/activity levels for spiked samples (e.g., recovery studies, linearity using dilution series).
- Reference methods (implied for initial characterization of native plasma samples).
- Expected chemical behavior and measurement principles (e.g., precision for known controls, analytical sensitivity's statistical derivation).
For the broader indication of aiding in predicting CHD risk, the document mentions "clinical evaluation and patient risk assessment" in conjunction with the Lp-PLA2 activity, implying that the output of the device (Lp-PLA2 activity level) contributes to a broader clinical decision-making process, rather than being a direct diagnostic ground truth itself.
8. The Sample Size for the Training Set
This information is not provided. The document describes validation studies demonstrating device performance, not the development or training of an AI algorithm from a dataset. For IVDs, the "training set" doesn't typically apply in the same way it does for machine learning algorithms. The process involves assay development, optimization, and then validation against established analytical performance goals.
9. How the Ground Truth for the Training Set Was Established
This information is not provided and is not applicable in the context of the document. As explained for point 8, the document is about validating an IVD assay, not training a machine learning model. The ground truth for developing and optimizing such an assay would typically involve highly characterized reference materials and established laboratory methods.
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
DIADEXUS, INC. C/O LORRY WEAVER HUFFMAN MYRAQA, INC. 3 LAGOON DR. SUITE 280 REDWOOD SHORES CA 94065
December 15, 2014
Re: K141575 Trade/Device Name: PLAC® Test for Lp-PLA2 Activity Lp-PLA2 Activity Test Calibrators Lp-PLA2 Activity Test Controls Regulation Number: 21 CFR 866.5600 Regulation Name: Low-density lipoprotein immunological test system Regulatory Class: II Product Code: NOE, JIT, JJX Dated: October 30, 2014 Received: November 3, 2014
Dear Ms. Lorry Huffman:
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
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electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
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,
Katherine Serrano -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) K141575
Device Name PLAC® Test for Lp-PLA2 Activity
Indications for Use (Describe)
The PLAC® Test for Lp-PLA2 Activity is an enzyme assay for the in vitro quantitative determination of Lp-PLA2 (lipoprotein-associated phospholipase A2) activity in EDTA-plasma and serum on automated clinical chemistry analyzers. Lp-PLA2 activity is to be used in conjunction with clinical evaluation and patient risk assessment as an aid in predicting risk of coronary heart disease (CHD) in patients with no prior history of cardiovascular events.
The Lp-PLA2 Activity Test Calibrators are intended to establish points of reference that are used in the determination of values in the measurement of Lp-PLA2 activity by the PLAC® Test for Lp-PLA2 Activity.
The Lp-PLA2 Activity Test Controls are intended for use as a quality control tool to monitor the performance within the clinical range of the PLAC® Test for Lp-PLA2 Activity, an enzyme assay for the quantitative determination of Lp-PLA2 activity
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) Summary - PLAC® Test for Lp-PLA2 Activity
1. Submitter Name:
diaDexus, Inc. 349 Oyster Point Blvd. South San Francisco, CA 94080 Contact: Emi Zychlinsky, Ph.D. Telephone: 650-246-6459
2. Correspondent/Contact
Lorry Weaver Huffman, Senior Director Myraqa, Inc. 3 Lagoon Dr., Suite 280 Redwood Shores, CA 94065 Phone: 1 (650) 730-5030 Mobile: 1 (916) 812-3047 Fax: 1 (916) 638-2647 E-mail: lorry@myraqa.com
3. Date Prepared: December 05, 2014
4. Device Name
| Trade Name (Proprietary Name): | PLAC® Test for Lp-PLA2 ActivityLp-PLA2 Activity Test CalibratorsLp-PLA2 Activity Test Controls |
|---|---|
| Common Name (Usual Name): | PLAC Activity |
| Panel: | Immunology |
| Measurand: | Lipoprotein-Associated Phospholipase A2 (Lp-PLA2) |
| Sample Type: | EDTA-plasma or serum |
| Type of Test: | Enzyme activity rate of change using a standardcurve |
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| Product | Regulation | Description | ProductCode |
|---|---|---|---|
| PLAC® Test forLp-PLA2 Activity | 866.5600 | Test, system,immunoassay,lipoprotein-associatedphospholipase A2 | NOE |
| Lp-PLA2 ActivityTest Calibrators | 862.1150 | Calibrators, Secondary | JIT |
| Lp-PLA2 ActivityTest Controls | 862.1660 | Quality Control Material(assayed and unassayed) | JJX |
5. Predicate Devices: K030477 - PLAC® Test
6. Device Description:
The PLAC® Test for Lp-PLA2 Activity consists of the reagents, Lp-PLA2 Activity Test Calibrators and Lp-PLA2 Activity Test Controls for the measurement of Lp-PLA2 activity in EDTA-plasma or serum on automated clinical laboratory analyzers.
Lp-PLA2, in plasma or serum, hydrolyzes the sn-2 position of the substrate, 1myristoyl-2-(4-nitrophenylsuccinyl) phosphatidylcholine, producing a colored reaction product, 4-nitrophenol. The rate of formation of 4-nitrophenol is measured spectrophotometrically for 8.5 minutes and the Lp-PLA2 activity is calculated from the rate of change in absorbance. A set of five Lp-PLA2 calibrators is used to generate a standard curve fit of change in absorbance versus Lp-PLA2 activity level in nmol/min/mL from which the sample Lp-PLA2 activity is derived.
The PLAC® Test for Lp-PLA2 Activity also includes controls. Controls should be included in each run or in accordance with the user's laboratory's quality control policies.
7. Intended Use:
The PLAC® Test for Lp-PLA2 Activity is an enzyme assay for the in vitro quantitative determination of Lp-PLA2 (lipoprotein-associated phospholipase A2) activity in EDTA-plasma and serum on automated clinical chemistry analyzers. Lp-PLA2 activity is to be used in conjunction with clinical evaluation and patient risk assessment as an aid in predicting risk of coronary heart disease (CHD) in patients with no prior history of cardiovascular events.
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The Lp-PLA2 Activity Test Calibrators are intended to establish points of reference that are used in the determination of values in the measurement of Lp-PLA2 activity by the PLAC® Test for Lp-PLA2 Activity.
The Lp-PLA2 Activity Test Controls are intended for use as a quality control tool to monitor the performance within the clinical range of the PLAC® Test for Lp-PLA2 Activity, an enzyme assay for the quantitative determination of Lp-PLA2 activity.
8. Summary of Technological Characteristics Compared to the Predicate Device:
The technological characteristics of the predicate device diaDexus PLAC® Test, 510(k) number K030477, differs in detection method from the device subject of this 510(k), diaDexus PLAC® Test for Lp-PLA2 Activity. In principle, both assays measure Lp-PLA3, however the predicate device measures concentration (ng/mL) and the subject assay measures enzymatic activity (nmol/min/mL).
The PLAC® Test for Lp-PLA2 Activity is for in vitro diagnostic use for quantitative determination of Lp-PLA2 activity. In the PLAC® Test for Lp-PLA2 Activity, Lp-PLA2 in plasma or serum, hydrolyzes the sn-2 position of the substrate, 1-myristoyl-2-(4-nitrophenylsuccinyl) phosphatidylcholine, producing 4-nitrophenyl succinate. The latter is immediately further hydrolyzed to produce the colored reaction product, 4-nitrophenol. spectrophotometrically at 410 nm and the Lp-PLA2 activity is calculated from the rate of change in absorbance. The predicate PLAC® Test is an ELISA immunoassay based on the principle of a sandwich enzyme immunoassay using two specific monoclonal antibodies for the direct measurement of Lp-PLA2 concentration. Absorbance of the colored by-product from the enzymatic turnover of the substrate by the enzyme labeled on the detection antibody is measured spectrophotometrically at 450 nm and is directly proportional to the concentration of Lp-PLA2 present.
The performance testing provided in this 510(k) is sufficient to demonstrate that PLAC® Test for Lp-PLA2 Activity is substantially equivalent to the legally marketed predicate device, diaDexus PLAC® Test, K030477. The comparison of assays similarities and differences are shown in Table 1.
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| Attribute | (Predicate Devices)PLAC® Test (K030477) | (Subject Device)PLAC® Test for Lp-PLA2 Activity |
|---|---|---|
| REAGENT KITIntended Use | The PLAC® Test is anenzyme immunoassay for thequantitative determination ofLp-PLA2 (lipoprotein-associated phospholipase A2)in human plasma, to be usedin conjunction with clinicalevaluation and patient riskassessment as an aid inpredicting risk for coronaryheart disease. | The PLAC® Test for Lp-PLA2Activity is an enzyme assay forthe in vitro quantitativedetermination of Lp-PLA2(lipoprotein-associatedphospholipase A2) activity inEDTA-plasma and serum onautomated clinical chemistryanalyzers. Lp-PLA2 activity isto be used in conjunction withclinical evaluation and patientrisk assessment as an aid inpredicting risk of coronary heartdisease (CHD) in patients withno prior history ofcardiovascular events. |
| REAGENT KITClassification Code | NOE - Test, system,immunoassay, lipoprotein-associated phospholipase A2 | Same |
| CALIBRATORSIntended Use | The PLAC® Test Calibratorsare intended to establishpoints of reference that areused in the determination ofvalues in the measurement ofLp-PLA2 by the PLAC® Test. | The Lp-PLA2 Activity TestCalibrators are intended toestablish points of referencethat are used in thedetermination of values in themeasurement of Lp-PLA2 bythe PLAC® Test for Lp-PLA2Activity. |
| CALIBRATORSClassification Code | JIT - Calibrators, Secondary | Same |
| CONTROLSIntended Use | The Lp-PLA2 Controls areintended for use as a qualitycontrol tool to monitor theperformance within theclinical range of the PLAC®Test, an immunoassay for thequantitative determination ofLp-PLA2. | The Lp-PLA2 Activity TestControls are intended for use asa quality control tool to monitorthe performance within theclinical range of the PLAC®Test for Lp-PLA2 Activity, anenzyme assay for thequantitative determination ofLp-PLA2 activity. |
| Attribute | (Predicate Devices)PLAC® Test (K030477) | (Subject Device)PLAC® Test for Lp-PLA2Activity |
| CONTROLSClassification Code | JJX - Enzyme controls(assayed and unassayed) | Same |
| Sample Source | EDTA plasma | SerumEDTA plasma |
| Assay method | Enzyme immunoassay(ELISA) | Enzyme kinetics activity rateof change using a standardcurve |
| Measurement units | Concentration, ng/mL | Activity, nmol/min/mL |
| Analyte | Lp-PLA2 | Same |
| Test Reagents | • Anti-Lp-PLA2 mAb coatedstripwells• Enzyme conjugate anti-Lp-PLA2 mAb-HRP• TMB substrate• Stop solution• Assay buffer• Reconstitution buffer• Sample diluent | • R1: Buffer• R2: Lp-PLA2 Substrate, 1-myristoyl-2-(4-nitrophenylsuccinyl)phosphatidylcholine |
| Calibration materials | A set of calibrators made withrecombinant Lp-PLA2 proteinin a protein matrix | A set of calibrators made withrecombinant Lp-PLA2 proteinin a protein buffered matrix |
| Control materials | 2 levels recombinant Lp-PLA2 protein in a stabilizingdiluent | Same |
| Sample Preparation | Sample diluent is added to thesample | No sample preparation isrequired |
| Instrument reader | Microtiter plate reader | Automated clinical chemistryanalyzer |
Table 1. Comparison of Assays
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9. Summary of Non-clinical Performance Testing as Basis for Substantial Equivalence
Studies were conducted to evaluate the performance characteristics of the PLAC® Test for Lp-PLA2 Activity. The studies include precision, analytical sensitivity (limit of detection/limit of the blank/limit of quantitation), linearity, recovery, interfering substances, specimen handling, stability, and matrix comparison.
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Precision
The precision of the PLAC® Test for Lp-PLA2 Activity was evaluated on one Beckman Coulter (Olympus) AU400® Clinical Chemistry Analyzer and three (3) kit lots according to CLSI EP5-A2. Four native plasma samples, kit control low, and kit control high with known amounts of Lp-PLA2 activity values ranging from 111 to 321 nmol/min/mL were tested with 2 replicates per run, 2 runs per day for 20 days. Total precision CV's for all kit lots and test samples were < 3%.
Table 2 summarizes the results of the precision studies performed for the PLAC® Test for Lp-PLA2 Activity.
| Lot | Sample | Mean(nmol/min/mL)N=80 | Within-Run(Repeatability) | Between-Run | Between-Day | Total* | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| AcceptanceCriteria | SD | %CV | SD | %CV | SD | %CV | SD | %CV | ||
| ≤5% | ≤8% | |||||||||
| Lot 1 | KitControlLow | 122.0 | 1.90 | 1.6% | 2.59 | 2.1% | 0.001 | 0.0% | 3.21 | 2.6% |
| KitControlHigh | 303.8 | 4.57 | 1.5% | 4.74 | 1.6% | 0.00 | 0.0% | 6.59 | 2.2% | |
| Sample 1 | 117.1 | 1.68 | 1.4% | 1.55 | 1.3% | 0.00 | 0.0% | 2.29 | 2.0% | |
| Sample 2 | 213.1 | 2.79 | 1.3% | 3.16 | 1.5% | 0.88 | 0.4% | 4.31 | 2.0% | |
| Sample 3 | 249.8 | 4.63 | 1.9% | 3.18 | 1.3% | 2.05 | 0.8% | 5.98 | 2.4% | |
| Sample 4 | 320.8 | 3.52 | 1.1% | 3.49 | 1.1% | 0.00 | 0.0% | 4.96 | 1.5% |
1 Values of 0.0 are actual calculated results rounded for values <0.05.
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| Within-Run(Repeatability) | Between-Run | Between-Day | Total* | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Lot | Sample | Mean(nmol/min/mL)N=80 | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| AcceptanceCriteria | ≤5% | ≤8% | ||||||||
| Lot 2 | KitControlLow | 118.1 | 1.60 | 1.4% | 2.14 | 1.8% | 0.65 | 0.6% | 2.75 | 2.3% |
| KitControlHigh | 297.7 | 3.90 | 1.3% | 4.78 | 1.6% | 3.00 | 1.0% | 6.86 | 2.3% | |
| Sample 1 | 110.7 | 1.29 | 1.2% | 1.79 | 1.6% | 0.60 | 0.5% | 2.28 | 2.1% | |
| Sample 2 | 203.0 | 3.26 | 1.6% | 1.89 | 0.9% | 4.10 | 2.0% | 5.57 | 2.7% | |
| Sample 3 | 237.9 | 3.42 | 1.4% | 3.57 | 1.5% | 4.70 | 2.0% | 6.83 | 2.9% | |
| Sample 4 | 305.9 | 3.07 | 1.0% | 4.84 | 1.6% | 2.95 | 1.0% | 6.44 | 2.1% | |
| KitControlHigh | 307.0 | 4.43 | 1.4% | 5.41 | 1.8% | 0.95 | 0.3% | 7.06 | 2.3% | |
| Sample 1 | 111.2 | 1.20 | 1.1% | 1.79 | 1.6% | 1.08 | 1.0% | 2.41 | 2.2% | |
| Sample 2 | 208.3 | 2.83 | 1.4% | 2.68 | 1.3% | 2.22 | 1.1% | 4.48 | 2.2% | |
| Sample 3 | 245.5 | 2.68 | 1.1% | 4.04 | 1.6% | 3.37 | 1.4% | 5.90 | 2.4% | |
| Sample 4 | 317.1 | 4.78 | 1.5% | 4.55 | 1.4% | 1.12 | 0.4% | 6.69 | 2.1% |
- Total Precision includes within-run, between-run, and between-day variance components
Analytical Sensitivity
The estimations of the Limit of Blank (LoB), Limit of Detection (LoD) and Limit of Quantitation (LoQ) were performed according to CLSI EP17-A2. The LoB was 0.40 nmol/min/mL, LoD of the assay was estimated to be 0.74 nmol/min/mL and the LoQ was 10 nmol/min/mL with an allowable CV of 20%.
Linearity
Linearity of the PLAC® Test for Lp-PLA2 Activity was assessed on one Beckman Coulter (Olympus) AU400® Clinical Chemistry Analyzer according to CLSI EP6-A using 3 kit lots. Several dilution series were prepared from native plasma samples
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with known high and low Lp-PLA2 activity levels. In the range of 6 to 382 nmol/min/mL, linear regression of Lp-PLA2 activity levels resulted in slopes ranging from 0.98 to 1.04. intercepts ranging from -0.4 to -0.03 nmol/min/mL and Re values ranging from 0.995 to 0.999. Linearity was demonstrated from 10 to 382 nmol/min/mL with a deviation from linearity of ≤10%.
The measuring range of the assay is determined to be 10 to 382 nmol/min/mL with the low end of the range based on the Limit of Quantitation
Recovery
Various amounts of a high Lp-PLA2 activity level solution were added to an enzymefree diluent to create seven activity levels. These spiked solutions were assayed with 3 lots of reagents and the Lp-PLA2 activity levels were then compared to expected values resulting in slopes ranging from 0.99 to 1.10, Intercepts ranging from -2.9 to 4.2 nmol/min/mL and R2 ranging from 0.997 to 1.000.
Analytical Specificity
Endogenous Interferences
The endogenous substances were titrated into four (4) plasma samples with known levels of each endogenous substance and five (5) replicates were tested for each level in a protocol developed according to CLSI EP7-A2. The following common substances, when added to plasma with Lp-PLA2 activity levels ranging from 85 to 315 nmol/min/mL, met acceptance criteria 90-110% recovery in the measured Lp-PLA2 activity level at the following levels:
| Potential EndogenousInterfering Substance | High Concentration MeetingAcceptance Criteria |
|---|---|
| Albumin | 60 g/L |
| Conjugated Bilirubin | 12 mg/dL |
| Unconjugated Bilirubin | 20 mg/dL |
| Cholesterol | 300 mg/dL |
| Triglycerides | 400 mg/dL |
| Hemoglobin | 1 mg/mL |
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Exogenous Substances
Exogenous substances (common and prescription drugs) were evaluated for interference in the assay following CLSI EP7-A2 guidelines. Four (4) native plasma samples ranging from 101 to 315 nmol/min/mL were spiked with two levels of each potential interferent and tested in duplicate. No appreciable interference was observed for the following substances at the spiked levels tested.
| Potential ExogenousInterfering Substance | Low Conc.(µmol/L) | High Conc.(µmol/L) |
|---|---|---|
| Acetaminophen | 33 | 1324 |
| Aspirin | 720 | 3600 |
| Atorvastatin | 2 | 20 |
| Diphenhydramine | 2 | 20 |
| Fenofibrate | 42 | 125 |
| Lisinopril | 0.25 | 0.74 |
| Niacin | 480 | 4800 |
| Tolbutamide | 400 | 2300 |
| Warfarin | 10 | 33 |
| Metformin | 31 | 310 |
| Clopidogrel bisulfate | 10 | 100 |
| Vitamin C | 14 | 342 |
Table 4 - Exogenous Interfering Substances and Test Concentrations
Specimen Handling and Stability
Specimen handling and stability was tested to assure accurate Lp-PLA2 activity results using plasma, serum and unprocessed whole blood under specified conditions for the PLAC® Test for Lp-PLA2 Activity on automated clinical chemistry analyzers.
The package insert states the following:
- . Process blood using standard separation procedures.
- Whole blood can be kept up to 4 hours at 20-22°C or up to 30 hours at 2-8℃ prior to separation.
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- . Following centrifugation:
- Examine for hemolysis. If present, discard sample and re-draw.
- . Sample can be tested immediately or stored prior to testing under the following conditions:
- 24 hours at 20-26°C .
- Up to 2 weeks at 2-8°C .
- Up to 18 months at -20°C .
- . Up to 2 years at -70°C
- . Sample can be tested immediately or stored prior to testing under the following conditions:
- Plasma and serum samples can be freeze/thawed up to 5 times after freezing at either -70°C or -20°C.
- When transporting samples, ship samples on cold packs at 2-8°C
- Examine for hemolysis. If present, discard sample and re-draw.
Reagent Stability
Shelf Life (2-8ºC)
Real-Time Stability testing demonstrates a 13-month shelf life for the PLAC® Test for Lp-PLA2 Activity kits. The labeled shelf life for each reagent when stored according to the listed conditions will be 12-months at 2-8°C.
Open Vial Stability (2-8°C)
Open vial stability testing was established at 16-weeks. The package insert states that opened reagents will be stable for 4-weeks when stored at 2-8℃. The package insert states that opened calibrators and controls will be stable for 3 months when stored at 2-8 ℃.
On-Board Reagent Stability 2-8°C
On-board Reagent Stability testing was established at 6-weeks. The package insert states that reagents stored on-board will be stable for 4-weeks at 2-8°C.
Matrix Comparison
A specimen matrix comparison study was performed using five (5) different blood collection tube matrices with one (1) reagent lot to evaluate suitability with the PLAC® Test for Lp-PLA2 Activity on one Beckman Coulter (Olympus) AU400® Clinical Chemistry Analyzer. The Lp-PLA2 activity values of the samples ranged from 56 to 357 nmol/min/mL and were tested in singlicate and compared to K2 EDTA plasma.
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All tube types (K3 EDTA plasma without separator gel, K2 EDTA plasma and serum with and without separator gel) were comparable to K2 EDTA plasma tube without separator gel.
10. Summary of Clinical Testing as Basis for Substantial Equivalence
Three aspects of Lp-PLA2 Activity were evaluated to establish the clinical performance of the assay: 1) Clinical validation in the intended use population; 2) Analysis of Lp-PLA2 Activity values in different ethnic groups; and 3) Clinical utility including benefit/risk of results. The clinical data provides evidence that the PLAC® Test for Lp-PLA2 Activity, used in conjunction with clinical evaluation and patient risk assessment, is an aid in predicting risk of coronary heart disease (CHD) in patients with no prior history of cardiovascular events. Clinical performance of the PLAC® Test for Lp-PLA2 Activity was successfully conducted meeting design input requirements and the intended use, and demonstrates that the assay system functions according to design specifications with both plasma and serum on automated clinical chemistry analyzers.
11. Conclusions Drawn from Non-clinical and Clinical Tests
Based on the information provided in this 510(k), the PLAC® Test for Lp-PLA2 Activity is substantially equivalent to the predicate device. The clinical and nonclinical studies demonstrate that the proposed device is as safe, as effective and performs as well as the predicate device per 807.92(b)(3).
§ 866.5600 Low-density lipoprotein immunological test system.
(a)
Identification. A low-density lipoprotein immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the low-density lipoprotein in serum and other body fluids. Measurement of low-density lipoprotein in serum may aid in the diagnosis of disorders of lipid (fat) metabolism and help to identify young persons at risk from cardiovascular diseases.(b)
Classification. Class II (performance standards).