The ARK™ Methotrexate Assay is a homogeneous enzyme immunoassay intended for the quantitative determination of methotrexate in human serum or plasma on automated clinical chemistry analyzers. The measurements obtained are used in monitoring levels of methotrexate to help ensure appropriate therapy.

Specimens from patients who have received glucarpidase (carboxypeptidase G2) as a high dose methotrexate rescue therapy should not be tested with the ARK Methotrexate Assay.

Device Description

The ARK Methotrexate Assay is a homogeneous immunoassay based on competition between drug in the specimen and Methotrexate labeled with the enzyme glucose-6-phosphate dehydrogenase (G6PDH) for binding to the antibody reagent. As the latter binds antibody, enzyme activity decreases. In the presence of drug from the specimen, enzyme activity increases and is directly proportional to the drug concentration. Active enzyme converts the coenzyme nicotinamide adenine dinucleotide (NAD) to NADH that is measured spectrophotometrically as a rate of change in absorbance. Endogenous serum G6PDH does not interfere with the results because the coenzyme NAD functions only with the bacterial enzyme used in the assay.

The ARK Methotrexate Assay consists of reagents R1 anti-Methotrexate polyclonal antibody with substrate and R2 Methotrexate labeled with bacterial G6PDH enzyme. The ARK Methotrexate Calibrator consists of a six-level set to calibrate the assay, and the ARK Methotrexate Control consists of a six-level set used for quality control of the assay (tri-level calibration range set and tri-level high range set). The ARK Methotrexate Dilution Buffer is equivalent to zero calibrator (Calibrator A).

AI/ML Overview

Here's an analysis of the provided text to extract the acceptance criteria and study information:

Acceptance Criteria and Device Performance for ARK™ Methotrexate Assay

The provided document describes the acceptance criteria and the study that proves the ARK™ Methotrexate Assay, when used on the Beckman Coulter AU680 analyzer, meets these criteria. The study aims to demonstrate substantial equivalence to the assay's performance on the predicate device, the Roche/Hitachi 917 analyzer.

1. Table of Acceptance Criteria and Reported Device Performance

The document states: "The pre-determined Pass/Fail acceptance criteria were met for all of the above performance studies." However, the specific numerical acceptance criteria or performance values for each characteristic are not provided in the given text. It only lists the types of performance characteristics evaluated.

Performance Characteristic	Acceptance Criteria (Not Detailed)	Reported Device Performance
Limit of Blank	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Limit of Detection	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Limit of Quantitation	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Recovery	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Linearity	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Accuracy (Method Comparison)	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Precision	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Specificity	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Cross-reactivity	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Carry-over	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
Dilution Recovery	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria
On-board Stability	Undisclosed Pass/Fail Criteria	Met Acceptance Criteria

2. Sample Size Used for the Test Set and Data Provenance

The document does not specify the sample sizes used for the test set for any of the performance studies.

The document refers to "human serum or plasma" as the sample type. The country of origin of the data is not explicitly stated. The study is a "validation and verification" activity, implying it was conducted specifically for this submission, likely making it a prospective study for the purpose of device validation.

3. Number of Experts and Qualifications for Ground Truth

The concept of "experts" and their qualifications for establishing ground truth, as typically seen in image analysis or diagnostic interpretation, is not applicable to this type of in vitro diagnostic device (immunoassay) study. The ground truth for this device's performance characteristics is established through analytical methods and reference standards, not expert interpretation.

4. Adjudication Method for the Test Set

The concept of an "adjudication method" (e.g., 2+1, 3+1) is not applicable to this type of in vitro diagnostic device (immunoassay) study. Performance is assessed through quantitative measurements against established analytical criteria, not through expert consensus on diagnostic outcomes.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

A Multi-Reader Multi-Case (MRMC) comparative effectiveness study is not applicable to this type of in vitro diagnostic device (immunoassay). This study design is typically used for imaging or diagnostic interpretation tasks where human readers' performance is being evaluated, often with and without AI assistance. This device is an automated assay, not an AI for human interpretive tasks.

6. Standalone (Algorithm Only) Performance Study

The study described is a standalone performance study for the algorithm (assay system) on the Beckman Coulter AU680 analyzer. The validation and verification activities listed (Limit of Blank, Limit of Detection, Accuracy, Precision, etc.) directly evaluate the performance of the device itself, without human interpretation in the loop. The purpose is to demonstrate that the assay system alone performs comparably to its predicate.

7. Type of Ground Truth Used

For an immunoassay like the ARK™ Methotrexate Assay, the "ground truth" for evaluating its performance characteristics (analytical accuracy, precision, linearity, etc.) would be established through:

Reference materials/standards: Calibrators and controls with precisely known concentrations of methotrexate.
Reference methods: Comparison with established, validated analytical methods (e.g., LC-MS/MS, or the predicate device's performance which was previously validated) for samples with unknown concentrations.
Spiking studies: Adding known amounts of analyte to a sample and measuring recovery to assess accuracy.

The document implicitly refers to these as part of the "analytical performance studies" and "validation and verification activities."

8. Sample Size for the Training Set

The document does not mention a training set or its sample size. This is expected as the ARK™ Methotrexate Assay is a homogeneous enzyme immunoassay kit, not a machine learning or AI model that requires a "training set" in the conventional sense. The "training" for such a system would involve validating its components and establishing its operational parameters on the target analyzer.

9. How Ground Truth for the Training Set Was Established

Since there is no "training set" in the context of machine learning, this question is not applicable. The assay is a chemical and biological system where parameters are set based on chemical principles and reagent characteristics, and then validated through performance studies.

Summary

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Image /page/0/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing right, stacked on top of each other.

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

ARK DIAGNOSTICS, INC. CHERRY MUN MANAGER, QUALITY AND REGULATORY AFFAIRS 48089 FREMONT BOULEVARD FREMONT CA 94538

Re: K163359

Trade/Device Name: ARK Methotrexate Assay Regulation Name: Unclassified, 510(k) required Product Code: LAO Dated: July 18, 2017 Received: July 19, 2017

Dear Cherry Mun:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

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

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

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

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(800) 638 2041 or (301) 796-7100 or at its Internet address

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

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

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

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

Sincerely yours,

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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Special 510(k) Summary

This summary of safety and effectiveness information for the ARK™ Methotrexate Assay System on the Beckman Coulter AU680 automated clinical chemistry analyzer is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

510(k) Number: K163359.

807.92 (a)(1): Name:	ARK Diagnostics, Inc.
Address:	48089 Fremont Blvd.Fremont, CA 94538
Owner Operator Number:	10027663
Establishment Registration:	3005755244
Phone:	(510) 270-6270
Fax:	(510) 270-6298
Contact:	Cherry Mun – (510) 270-6288Manager, Quality and Regulatory Affairs

Date Prepared: August 15, 2017

807.92 (a)(2): Device name – trade name and common name, and classification

Trade Name:	ARK™ Methotrexate Assay
Common Name:	Homogeneous Enzyme Immunoassay
Classification:	21 CFR 862 Clinical Chemistry Test System -Toxicology (91); Test Code LAO; EnzymeImmunoassay, Methotrexate Pre-AmendmentDevice, Unclassified

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807.92 (a)(3): Identification of the legally marketed predicate device

Performance of the ARK Methotrexate Assay was established on the Roche/Hitachi 917 analyzer in the original 510(k) (K111904).

807.92 (a)(4): Device Description

807.92 (a)(5): Intended Use / Indications for Use

Specimens from patients who have received glucarpidase (carboxypeptidase G2) as a high dose methotrexate rescue therapy should not be tested with the ARK Methotrexate Assay.

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Modification: The purpose of this submission is for a change in the platform analyzer used in the manufacture qualification of the ARK Methotrexate Assay from the Roche/Hitachi 917 analyzer to the Beckman Coulter AU680 analyzer.

807.92 (a)(6): Technological Similarities and Differences to the Predicate

Characteristic	DeviceARKTM Methotrexate Assay –Beckman Coulter AU680	PredicateARKTM Methotrexate Assay– Roche/Hitachi 917
Intended Use	The ARKTM Methotrexate Assay isintended for the quantitativedetermination of methotrexate in humanserum or plasma on automated clinicalchemistry analyzers.	Same
Indications forUse	The measurements obtained are used inmonitoring levels of methotrexate tohelp ensure appropriate therapy.	Same
Sample	Serum or plasma	Same
Methodology	Homogenous enzyme immunoassay(EIA)	Same
ReagentComponents	Two (2) reagent system:Anti-Methotrexate Antibody/SubstrateReagent (R1) containing rabbitpolyclonal antibodies to Methotrexate,glucose-6-phosphate, nicotinamideadenine dinucleotide, bovine serumalbumin, preservatives, and stabilizersEnzyme Reagent (R2) containingMethotrexate labeled with bacterialG6PDH, buffer, bovine serum albumin,preservatives, and stabilizers	Same
Platform Required	Automated clinical chemistry analyzer	Same
AccessoryReagents	Calibrators (six levels) and controls (sixlevels) in a synthetic matrix; DilutionBuffer	Same
TestingEnvironment	Routine clinical laboratory	Same
ReagentCondition andStorage	Liquid, 2-8° C	Same

SUBSTANTIAL EQUIVALENCE COMPARATIVE CHART

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807.92 (b)(1) and 807.92 (b)(2): Brief Description of Nonclinical and Clinical Data

Validation and verification activities were performed which included analytical performance studies to ensure that the performance of the ARK Methotrexate Assay as used on the Beckman Coulter AU680 analyzer is substantially equivalent to the performance of the assay as used on the Roche/Hitachi 917 analyzer (K111904). The following performance characteristics were evaluated:

Limit of Blank ●
Limit of Detection
Limit of Quantitation
Recovery ●
Linearity
Accuracy (Method Comparison)
Precision
. Specificity
Cross-reactivity
Carry-over ●
Dilution Recovery ●
On-board Stability .

The pre-determined Pass/Fail acceptance criteria were met for all of the above performance studies.

807.92 (b)(3): Conclusions from Nonclinical Testing

The ARK Methotrexate Assay System (including the ARK Methotrexate Calibrator, ARK Methotrexate Control and ARK Methotrexate Dilution Buffer) as applied on the Beckman Coulter AU680 automated clinical chemistry analyzer is substantially equivalent to the ARK Methotrexate Assay System on the Roche/Hitachi 917 automated clinical chemistry analyzer. The ARK Methotrexate Assay System was shown to be safe and effective for its intended use based on performance studies.

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Regulation Number and Section

N/A