The ARK™ Gabapentin Assay is a homogeneous enzyme immunoassay intended for the quantitative determination of gabapentin in human serum or plasma on automated clinical chemistry analyzers. Gabapentin concentrations can be used as an aid in management of patients treated with gabapentin.

The ARKTM Gabapentin Calibrator is intended for use in calibration of the ARK Gabapentin Assay.

The ARKTM Gabapentin Control is intended for use in quality control of the ARK Gabapentin Assay.

Device Description

The ARK Gabapentin Assay is a homogeneous immunoassay based on competition between drug in the specimen and gabapentin 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 coenyzme NAD functions only with the bacterial enzyme used in the assay.

The ARK Gabapentin Assay consists of reagents R1 anti-gabapentin polyclonal antibody with substrate and R2 gabapentin labeled with bacterial G6PDH enzyme. The ARK Gabapentin Calibrator consists of a six-level set to calibrate the assay, and the ARK Gabapentin Control consists of a three-level set used for quality control of the assay.

ARK Gabapentin products contain ≤0.09% sodium azide. As a precaution, affected plumbing should be flushed adequately with water to mitigate the potential accumulation of explosive metal azides. No special handling is required regarding other assay components.

AI/ML Overview

Here's a summary of the acceptance criteria and study findings for the ARK™ Gabapentin Assay, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

Performance Metric	Acceptance Criteria	Reported Device Performance
Limit of Quantitation (LOQ)	≤20% CV with ±15% recovery	0.75 µg/mL (demonstrated acceptable inter-assay precision and recovery)
Recovery / Accuracy	Not explicitly stated as a defined criterion (implied by typical assay validation standards that recovery should be close to 100% within a certain range).	Mean percent recovery: 100.9% across concentrations from 1.0 to 40.0 µg/mL.
Linearity	Percent difference between predicted 1st and 2nd order regressed values of ±10%, or ±15% for concentrations ≤ 1.0 µg/mL.	Linear relationship demonstrated between 0.75 and 48.0 µg/mL. All points met the ±10% or ±15% (for lower concentrations) difference criteria. (e.g., 0.75 µg/mL: 12.0% difference; 1.0 µg/mL: 8.4% difference; all others below 2.2% difference up to 48 µg/mL).
Assay Range	Not explicitly stated as an acceptance criterion for the range itself, but the device performance defines the reportable range.	0.75 to 40.0 µg/mL.
Method Comparison (Correlation)	Implied by the use of Passing-Bablok regression: a slope close to 1, y-intercept close to 0, and a high correlation coefficient (r²) indicating strong agreement with reference methods.	Study 1 (LC-MS/MS): Slope 0.96 (0.92 to 0.99), y-intercept -0.06 (-0.28 to 0.18), r² 0.96 (0.95 to 0.97). Study 2 (HPLC): Slope 1.08 (1.03 to 1.13), y-intercept -0.08 (-0.35 to 0.25), r² 0.97 (0.95 to 0.98). Study 3 (LC-MS/MS): Slope 1.13 (1.08 to 1.17), y-intercept 0.31 (0.06 to 0.52), r² 0.98 (0.97 to 0.99).
Precision	<10% total CV	ARK Gabapentin Control: Low 5.6%, Mid 4.4%, High 3.6% (total CV). Human Serum: Low 7.7%, Mid 4.6%, High 4.7% (total CV). All met the <10% total CV criterion.
Interfering Substances	Measurement of gabapentin resulted in ≤10% error in the presence of interfering substances at the levels tested.	All tested substances (Albumin, Bilirubin Conjugated/Unconjugated, Cholesterol, Gamma-Globulin, Hemoglobin, Intralipid®, Rheumatoid Factor, Triglycerides, Uric Acid) resulted in percentage recovery between 95.2% and 106.6% (i.e., within 10% error) for gabapentin concentrations of 2 µg/mL and 20 µg/mL.
Drug Interference	Measurement of gabapentin resulted in ≤10% error in the presence of drug compounds at the levels tested.	Most tested anti-epileptic or co-administered drugs and L-amino acids showed percentage recovery within 10% error (between 90% and 110%) for both 2 µg/mL and 20 µg/mL gabapentin. Note: Pregabalin showed higher cross-reactivity at high concentrations (e.g., 100 µg/mL Pregabalin led to 156.9% recovery at 2 µg/mL Gabapentin). The document notes that "Care should be taken when interpreting ARK Gabapentin results if pregabalin is also being administered."
Anticoagulants	Not explicitly stated as a numerical criterion, but implies no significant difference.	"The results indicate that there is no significant difference between the recovery of gabapentin in serum or plasma."
Sample Stability	Fresh specimens preferred. Clarified specimens: up to one week at 2-8°C. Frozen (≤ -10°C): up to four weeks (acceptance criterion ± 10%). Withstand 3 freeze-thaw cycles.	Specimens shown to meet these criteria.
On-Board Stability (Calibration Curve)	Up to 84 days.	Effective up to 84 days based on supporting data.
On-Board Stability (Reagent)	Up to at least 84 days.	Effective up to at least 84 days based on supporting data.
Accelerated OPEN stability of calibrators and controls	Calibrators and controls stable OPEN at 37℃ for seven (7) days. Once opened: 12 months at 2-8℃.	Shown to be stable per criteria.

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

Recovery: Not explicitly stated how many unique samples were tested, but "Six replicates of each sample were assayed." The samples were "human serum negative for gabapentin" spiked with pure gabapentin. Provenance: Not specified (retrospective/prospective, country of origin).
Linearity: Not explicitly stated how many unique samples, but dilutions were made from a 48.0 µg/mL serum sample. Provenance: Not specified.
Method Comparison:
- Study 1: 183 samples. Provenance: Not specified.
- Study 2: 64 samples. Provenance: Not specified.
- Study 3: 49 samples. Provenance: Not specified.
Precision: 160 measurements were taken for each of the three control levels and three human serum pooled specimens (quadruplicate, twice a day for 20 days). Provenance: Not specified.
Interfering Substances: For each interfering substance, samples were prepared with gabapentin at approximately 2 µg/mL and 20 µg/mL, and assayed against a serum control. The number of individual samples (beyond the spiked ones) isn't specified. Provenance: Not specified.
Drug Interference: Similar to interfering substances, samples were prepared with gabapentin at approximately 2 µg/mL and 20 µg/mL, spiked with high concentrations of various drugs, and assayed against a serum control. Provenance: Not specified.
Anticoagulants: "Studies were conducted to determine the performance characteristics of the assay for both serum and plasma samples." Specific sample sizes not provided. Provenance: Not specified.
Sample Stability: Specific sample sizes not provided, but studies addressed various storage conditions and freeze-thaw cycles. Provenance: Not specified.

It is common for these types of in vitro diagnostic device submissions for a new assay to describe the preparation of test materials and not necessarily the specific provenance of every human sample component (e.g., general "human serum").

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This type of in vitro diagnostic device (quantitative immunoassay) does not typically involve human experts for establishing "ground truth" in the way an imaging AI device would. Instead, the "ground truth" for the performance studies described is established by:

Reference methods: For method comparison, reference standards like LC-MS/MS and HPLC are used to define the true concentration of gabapentin in samples. These are highly accurate analytical techniques, not human expert consensus.
Spiking studies: For recovery, linearity, interference, and drug interference, known quantities of high-purity gabapentin or interfering substances are added to negative serum/plasma, establishing a precise theoretical "ground truth" concentration.

Therefore, the concept of "number of experts" and their "qualifications" for ground truth determination is not applicable in this context.

4. Adjudication Method for the Test Set

Not applicable. As explained above, the ground truth is established by analytical reference methods or known spiked concentrations, not by human interpretation or adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

Not applicable. This device is a quantitative immunoassay for measuring drug concentration in blood, not an imaging device or a diagnostic aid that would involve human "readers" or AI assistance in interpretation.

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

Yes, the studies described are all "standalone" in nature, as they assess the performance of the assay itself (the "algorithm only" in a broader sense of an analytical method) to accurately measure gabapentin concentrations. The output of the device is a quantitative value (gabapentin concentration in µg/mL), which is then used by clinicians. There is no "human-in-the-loop performance" component for how the assay itself functions.

7. The Type of Ground Truth Used

The ground truth for the performance studies was established using:

Reference analytical methods: High Performance Liquid Chromatography - Mass Spectrometry (LC-MS/MS) and High Performance Liquid Chromatography (HPLC) were used as reference methods for the method comparison studies.
Spiked samples: For recovery, linearity, interference, and drug interference studies, known, precise amounts of pure gabapentin or interfering substances were added to gabapentin-negative human serum/plasma to create samples with known theoretical concentrations.

8. The Sample Size for the Training Set

Not applicable. This is an immunoassay, not a machine learning or AI algorithm in the contemporary sense that would involve a "training set" for model development. The development of the assay (e.g., antibody selection, reagent formulation) is a traditional chemical and biological process, not a computational learning process with distinct training and test sets.

9. How the Ground Truth for the Training Set was Established

Not applicable, as there is no "training set" in the context of this immunoassay.

Summary

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510(k) SUMMARY

NOV 2 3 2010

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

The assigned 510(k) number is K101574.

807.92 (a)(1): Name:	ARK Diagnostics, Inc.
Address:	1190 Bordeaux DriveSunnyvale, CA 94089
Owner Operator Number:	10027663	Establishment Registration:	3005755244
Phone:	(408) 747-0700
FAX:	(408) 747-0783
Contact:	Kenneth C. Kasper, PhD – (408) 747-0708Executive Director of Quality and Regulatory Affairs

Date prepared: November 23, 2010

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

Trade name:	ARKTM Gabapentin AssayARKTM Gabapentin CalibratorARKTM Gabapentin Control
Common Name:	Homogeneous Enzyme Immunoassay
Classification:	21 CFR 862.3350 NWM Diphenylhydantoin Test System; Class II(21 CFR 862.3200 DLJ, 21 CFR 862.3280 LAS)

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

ARKTM Topiramate Assay ARK™ Topiramate Calibrator ARK™ Topiramate Control

K083799 (bundled)

Image /page/0/Picture/11 description: The image contains a black circle on a white background. The circle is located on the left side of the image. The circle is solid black and has a smooth edge. The rest of the image is white.

ARK Diagnostics, Inc. - 510(k) Summary ARK Gabapentin Assay

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807.92 (a)(4): Device Description

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

The ARKTM Gabapentin Calibrator is intended for use in calibration of the ARK Gabapentin Assay.

The ARKTM Gabapentin Control is intended for use in quality control of the ARK Gabapentin Assay.

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

SUBSTANTIAL EQUIVALENCE COMPARATIVE CHART

Characteristic	Device	Predicate
	ARK™ Gabapentin Assay	ARK™ Topiramate Assay K083799
Intended Use	The ARK™ Gabapentin Assay is intendedfor the quantitative determination ofgabapentin in human serum or plasma onautomated clinical chemistry analyzers.	The ARK™ Topiramate Assay is intendedfor the quantitative determination oftopiramate in human serum or plasma onautomated clinical chemistry analyzers.
Indications for Use	Gabapentin concentrations can be used as anaid in management of patients treated withgabapentin.	The results obtained are used in the diagnosisand treatment of topiramate overdose and inmonitoring levels of topiramate to helpensure appropriate therapy.
Sample	Serum or plasma	Serum or plasma
Methodology	Homogenous enzyme immunoassay (EIA)	Homogenous enzyme immunoassay (EIA)
Reagent Components	Two (2) reagent system:	Two (2) reagent system:
	Anti- gabapentin Antibody/SubstrateReagent (R1) containing rabbit polyclonalantibodies to gabapentin, glucose-6-phosphate, nicotinamide adeninedinucleotide, bovine serum albumin, sodiumazide, and stabilizers	Anti-topiramate Antibody/Substrate Reagent(R1) containing rabbit polyclonal antibodiesto an epitope of topiramate, glucose-6-phosphate, nicotinamide adeninedinucleotide, bovine serum albumin,preservatives, and stabilizers
	Enzyme Reagent (R2) containing gabapentinlabeled with bacterial G6PDH, buffer, bovineserum albumin, sodium azide, and stabilizers	Enzyme Reagent (R2) containing topiramateepitope labeled with bacterial G6PDH,buffer, bovine serum albumin, preservatives,and stabilizers
Platform required	Automated clinical chemistry analyzer	Automated clinical chemistry analyzer
Accessory reagents	Calibrators (six levels) and controls (threelevels)	Calibrators (six levels) and controls (threelevels)
Testingenvironment	Routine clinical laboratory	Routine clinical laboratory
Reagent conditionand storage	Liquid, 2-8° C	Liquid, 2-8° C

Comparison between the ARK™ Gabapentin Assay and the ARK™ Topiramate Assay

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ARK Diagnostics, Inc. - 510(k) Summary ARK Gabapentin Assay

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

Limit of Quantitation (LOQ)

The LOQ of the ARK Gabapentin Assay was determined according to CLSI EP17-A and is defined as the lowest concentration for which acceptable inter-assay precision and recovery is observed (≤20% CV with ±15% recovery). The LOQ was determined to be 0.75 ug/mL.

Recovery

Accuracy (analytical recovery) was performed by adding concentrated gabapentin drug into human serum negative for gabapentin. A stock concentrate of highly pure gabapentin was added volumetrically to human serum negative for gabapentin, representing drug concentrations across the assay range. Six replicates of each sample were assayed on an automated clinical chemistry analyzer. The results were averaged and compared to the target concentration and percent recovery calculated. Results are shown below.

	% Recovery = 100 X Mean recovered concentration
	Theoretical concentration

TheoreticalConcentration(µg/mL)	Mean RecoveredConcentration(µg/mL)	PercentRecovery
1.0	0.99	98.5
2.0	2.07	103.3
3.5	3.55	101.3
9.0	8.98	99.7
16.0	16.03	100.2
22.0	22.00	100.0
28.0	27.85	99.5
35.0	35.59	101.7
40.0	41.49	103.7

Mean percent recovery: 100.9%

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Linearitv

Linearity studies were performed as suggested in CLSI/NCCLS Protocol EP6-A. A 48.0 µg/mL serum sample was prepared and dilutions were made proportionally with human serum negative for gabapentin. Gabapentin concentrations ranged from 0.75 to 48.0 µg/mL. Linearity at specific dilutions was considered acceptable if the percent difference was ±10% between the predicted 1st and 2nd order regressed values or ±15% ≤ 1.0 µg/mL. A linear relationship was demonstrated between 0.75 and 48.0 µg/mL. Results are shown below.

Theoretical(µg/mL)	Results(ug/mL)	1st OrderPredictedResults	2nd OrderPredictedResults	% Difference
0.75	0.73	0.76	0.85	12.0
1.0	1.0	1.0	1.1	8.4
2.4	2.4	2.4	2.4	2.2
3.2	3.3	3.2	3.2	1.1
4.8	4.9	4.8	4.8	0.0
8.0	8.0	8.0	7.9	-0.7
12.0	11.9	12.0	11.9	-0.9
24.0	23.6	23.9	23.8	-0.6
32.0	31.8	31.9	31.8	-0.3
40.0	39.7	39.8	39.9	0.2
48.0*	48.1	47.8	48.1	0.6

*Concentration exceeds the reportable limit.

Assay Range

The range of the assay is 0.75 to 40.0 µg/mL. Report results below this range as <0.75 µg/mL or below the analyzer-specific lower LOQ established in your laboratory. Report results above this range as >40.0 µg/mL or above the analyzer-specific upper LOQ established in your laboratory.

Specimens testing initially above the assay range may be diluted in Calibrator A and retested. Multiply the assay result by the dilution factor to obtain the concentration of gabapentin in the undiluted specimen. A dilution factor of 4 is suggested.

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Method Comparison

Correlation studies were performed using CLSI/NCCLS Protocol EP9-A2. Results from the ARK Gabapentin Assay were compared with results from three study sites using high performance liquid chromatography - mass spectrometry methods (LC-MS/MS, Study 1), HPLC (Study 2) and LC-MS/MS (Study 3).

Study 1

Gabapentin concentrations by LC-MS/MS ranged 1.0 to 39.0 µg/mL. ARK gabapentin values ranged 0.6 to 34.4 ug/mL Results of the Passing-Bablok23 regression analysis for the study are shown below (with 95% confidence limits).

Slope	0.96	(0.92 to 0.99)
y-intercept	- 0.06	(-0.28 to 0.18)
Correlation Coefficient (r2)	0.96	(0.95 to 0.97)
Number of Samples	183

Image /page/5/Figure/5 description: This image is a scatter plot comparing two different methods of measuring Gabapentin levels. The x-axis represents the LC-MS/MS method, while the y-axis represents the ARK Gabapentin Assay, both measured in micrograms per milliliter. The plot includes two lines: one representing the identity line and another representing the Passing & Bablok fit, with the equation (-0.06 + 0.96x).

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Study 2

Gabapentin concentrations by HPLC ranged from 1.8 to 29.4 µg/mL. ARK gabapentin values ranged 1.6 to 32.6 µg/mL. Results of the Passing-Bablok35 regression analysis for the study are shown below (with 95% confidence limits).

Slope	1.08	(1.03 to 1.13)
y-intercept	-0.08	(-0.35 to 0.25)
Correlation Coefficient ( $r^2$ )	0.97	(0.95 to 0.98)
Number of Samples	64

Image /page/6/Figure/3 description: The image is a scatter plot comparing two different assays for Gabapentin. The x-axis represents the results from Study 2: HPLC (µg/mL), while the y-axis represents the results from the ARK Gabapentin Assay (µg/mL). The plot includes a line of identity and a Passing & Bablok fit line, with the equation (-0.08 + 1.08x) displayed. The data points are clustered around the lines, indicating a correlation between the two assays.

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Study 3

Gabapentin concentrations by LC-MS/MS ranged 1.4 to 29.6 µg/mL. ARK gabapentin values ranged 1.6 to 32.6 µg/mL. Results of the Passing-Bablok25 regression analysis for the study are shown below (with 95% confidence limits).

Slope	1.13	(1.08 to 1.17)
y-intercept	0.31	(0.06 to 0.52)
Correlation Coefficient (r²)	0.98	(0.97 to 0.99)
Number of Samples	49

Image /page/7/Figure/3 description: This image is a scatter plot comparing two different assays for Gabapentin. The x-axis represents the LC-MS/MS assay in micrograms per milliliter, while the y-axis represents the ARK Gabapentin Assay, also in micrograms per milliliter. The plot includes a line of identity and a Passing & Bablok fit line, which is represented by the equation y = 0.31 + 1.13x. The data points are clustered around the lines, indicating a correlation between the two assays.

Image /page/7/Picture/4 description: The image shows a black circle in the upper left corner. Below the circle, the text "ARK Diagnos" is visible. The text is in a simple, sans-serif font and appears to be part of a larger document or logo.

ARK Diagnostics, Inc. – 510(k) Summary ARK Gabapentin Assay

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Precision

Precision was determined as described in CLSI/NCCLS Protocol EPS-A2. Tri-level controls and three human serum pooled specimens containing gabapentin were used in the study. Each level was assayed in quadruplicate twice a day for 20 days. Each of the runs per day was separated by at least two hours. The within run, between day, total SD, and percent CVs were calculated. Results are shown below. Acceptance criteria: <10% total CV.

				Within Run		Between Day		Total
Sample	N	Mean(µg/mL)	SD	CV(%)	SD	CV(%)	SD	CV(%)
ARK Gabapentin Control
LOW	160	2.5	0.08	3.3	0.10	3.9	0.14	5.6
MID	160	7.9	0.21	2.6	0.26	3.3	0.35	4.4
HIGH	160	24.6	0.48	1.9	0.65	2.7	0.88	3.6
Human Serum
LOW	160	2.2	0.11	4.7	0.11	4.8	0.17	7.7
MID	160	7.3	0.58	2.4	0.25	3.4	0.33	4.6
HIGH	160	24.9	0.54	2.2	0.97	3.9	1.17	4.7

Image /page/8/Picture/3 description: The image shows a solid black circle. The circle is slightly irregular in shape, with some minor imperfections along its perimeter. The background is plain white, providing a stark contrast to the black circle. The image is simple and minimalist, focusing solely on the shape and color of the circle.

ARK Diagnostics, Inc. - 510(k) Summary ARK Gabapentin Assay

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Interfering Substances

Interference studies were conducted using CLSI/NCCLS Protocol EP7-A2 as a guideline. Clinically high concentrations of the following potentially interfering substances in serum with known levels of gabapentin (approximately 2 and 20 ug/mL) were evaluated. Each sample was assayed using the ARK Gabapentin Assay, along with a serum control of gabapentin. Measurement of gabapentin resulted in ≤10% error in the presence of interfering substances at the levels tested.

		Percentage Recovery
InterferingSubstance	InterferentConcentration	2 ug/mLGabapentin	20 ug/mLGabapentin
Albumin	12 g/dL	102.1	98.2
Bilirubin Conjugated	70 mg/dL	95.2	98.3
Bilirubin Unconjugated	70 mg/dL	106.6	98.4
Cholesterol	623 mg/dL	101.6	98.0
Gamma-Globulin	12 g/dL	103.2	99.7
Hemoglobin	1000 mg/dL	102.5	101.6
Intralipid®	1500 mg/dL	97.0	99.2
Rheumatoid Factor	1100 IU/mL	97.0	97.1
Triglycerides	1220 mg/dL	105.6	99.6
Uric Acid	30 mg/dL	106.6.	97.9

Specificitv

Gabapentin is eliminated from the systemic circulation solely by renal excretion as unchanged drug and is not appreciably metabolized in humans. Therefore, no metabolites are known to result that could interfere in the measurement of gabapentin.

Medications that may be routinely co-administered with gabapentin, anti-epileptic drugs or Lamino acids were tested to determine whether these compounds affect the quantitation of gabapentin concentrations using the ARK Gabapentin Assay. High levels of these compounds were spiked into serum pools containing low (2 µg/mL) and high (20 µg/mL) therapeutic levels of gabapentin. The samples were analyzed and the gabapentin concentrations of samples containing co-administered with gabapentin, anti-epileptic drugs or L-amino acids were compared to the serum control.

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Drug Interference

Gabapentin-selective antibody did not crossreact with most other anti-epileptic or coadministered drugs tested. Due to structural similarities with gabapentin, high pregabalin levels may interfere. A high concentration of each compound was spiked into normal human serum with known levels of gabapentin (approximately 2 and 20 µg/mL) and assayed along with a serum control of gabapentin. Measurement of gabapentin resulted in ≤10% error in the presence of drug compounds at the levels tested.

Compound	Concentration(µg/mL)	Percentage Recovery
		Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)
γ-Aminobutyric Acid	100	97.8	99.2
L-2-Aminobutyric Acid	100	98.6	99.2
Acetaminophen	200	98.7	98.1
Acetazolamide	100	99.2	98.6
Acetylsalicylic acid	1000	100.6	100.4
Amikacin	100	100.2	98.7
Amitriptyline	20	98.2	97.9
Amoxapine	40	98.9	99.6
Amphotericin B	100	98.2	98.2
Ampicillin	100	100.8	100.0
Ascorbic Acid	100	97.3	98.3
Baclofen	100	103.3	100.6
Buproprion	40	106.9	100.6
Caffeine	100	99.8	99.8
Carbamazepine	120	99.4	98.9
Carbamazepine- 10, 11 epoxide	120	98.9	98.9
10-Hydroxy carbamazepine	100	102.8	100.4
Chloramphenicol	250	101.4	96.7
Chlorpromazine	20	103.1	100.8
Citalopram	20	102.8	100.8
Clobazam	100	96.3	108.0
Clonazepam	20	101.2	101.4
Cyclosporin A	40	95.1	97.2
Diazepam	20	102.6	100.5
Digoxin	80	103.0	101.8
Doxepin	20	103.9	101.2
Erythromycin	200	97.9	98.9
Ethanol	4000 (0.4%)	105.2	99.3
Ethotoin	100	97.1	97.5
Ethosuximide	250	95.8	99.6
Felbamate	250	98.2	99.1
Fluoxetine	20	103.8	101.2
Furosemide	100	95.2	98.0

ARK Diagnostics, Inc. - 510(k) Summary ARK Gabapentin Assay

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f

Compound	Concentration(µg/mL)	Percentage Recovery
		Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)
Gentamicin	100	100.0	100.4
Haloperidol	20	102.5	101.7
Heparin	200 U/mL	94.8	96.2
Ibuprofen	500	96.5	96.9
Imipramine	20	101.2	101.1
Kanamycin B	200	96.7	101.3
Lamotrigine	250	102.9	95.9
Levetiracetam	400	97.4	96.0
Lidocaine	100	97.7	98.7
Lincomycin	1000	102.4	100.4
Mephenytoin	100	100.6	99.6
Mesoridazine	40	106.2	96.2
Methicillin	250	101.5	98.0
Naproxen	600	100.2	97.3
Neomycin	1000	97.8	102.1
Niacin	100	98.9	100.3
Nitrazepam	20	96.5	97.5
Nortriptyline	20	101.6	97.1
Olanzapine	20	99.9	98.5
Oxcarbazepine	200	100.9	100.8
Paroxetine	40	102.4	96.0
2-phenyl-ethyl--malonamide(PEMA)	1000	105.8	98.7
Penicillin V	100	95.8	99.0
Perphenazine	100	102.4	99.0
Phenobarbital	200	100.3	98.3
Phenytoin	200	96.9	93.6
Primidone	100	93.0	99.1
Procainamide	100	95.9	95.9
Prochlorperazine	40	97.8	98.7
Ranitidine	100	97.2	98.3
Rifampin	100	95.3	102.4
Risperidone	20	101.8	103.2
Sertraline	100	98.5	97.5
Spectinomycin	100	98.3	102.1
Stiripentol	100	95.9	96.7
Sulfamethoxazole	400	97.5	98.0
Theophylline	200	103.0	100.5
Thioridazine	20	102.6	102.5
Tobramycin	100	94.6	100.3
Tiagabine	200	91.6	97.9
Topiramate	250	96.0	96.0

ARK Diagnostics, Inc. – 510(k) Summary ARK Gabapentin Assay

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	Concentration	Percentage Recovery
Compound	(µg/mL)	Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)
Trimethoprim	40	96.7	99.0
Valproic Acid	600	96.7	96.9
Vancomycin	250	100.3	99.8
Vigabatrin	150	101.3	99.9
Zonisamide	400	98.6	104.1

L-Amino Acid Interference

The L-amino acids listed below resulted in <10% error in detecting gabapentin at the concentrations tested.

Compound	Concentration(µg/mL)	Percentage Recovery
		Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)
L-Arginine	100	96.9	104.4
L-Asparagine	100	95.1	101.8
L-Aspartic Acid	25	93.9	102.0
L-Cysteine	25	92.6	101.9
L-Glutamic Acid	100	95.7	101.4
L-Glycine	100	98.0	100.8
L-Histidine	100	92.2	102.5
L-Isoleucine	100	92.2	101.9
L-Leucine	100	96.3	101.5
L-Methionine	25	93.3	100.9
L-Phenylalanine	50	94.4	99.6
L-Serine	50	95.1	99.3
L-Threonine	100	95.6	100.7
L-Tyrosine	100	93.9	99.0
L-Alanine	150	98.9	97.0
L-Lysine	150	97.8	98.2
L-Proline	150	96.0	98.3
L-Valine	150	97.5	97.7
L-Tryptophan	150	98.0	99.1
L-Glutamine	350	97.3	96.9

Drug that Interferes - Pregabalin

Pregabalin was analyzed from 15 to 100 µg/mL in the presence of either Low (2 µg/mL) or High (20 ug/mL) gabapentin. High concentrations of pregabalin may interfere by elevating the measurement of gabapentin. Pregabalin plasma levels in patients under therapy have been reported to range from approximately 0.2 to 14.2 µg/mL. Excessive pregabalin levels up to 60

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ug/mL in combination with lamotrigine in a self poisoning incident have been reported. The results of interference testing are shown below.

Pregabalin(µg/mL)	Percent Cross-Reactivity		Percent Recovery
	Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)	Gabapentin(2 µg/mL)	Gabapentin(20 µg/mL)
100	1.10	1.95	156.9	109.7
50	1.18	2.06	130.6	105.1
15	1.13	- 1.47	108.9	98.9

Care should be taken when interpreting ARK Gabapentin results if pregabalin is also being administered to the patient.

Anticoagulants

Studies were conducted to determine the performance characteristics of the assay for both serum and plasma samples containing gabapentin. The results indicate that there is no significant difference between the recovery of gabapentin in serum or plasma.

Sample Stability

Testing of fresh specimens is preferred. Clarified specimens may be stored up to one week at 2 to 8°C. If testing will be delayed more than one week, specimens may be stored frozen (≤ -10°C) up to four weeks prior to being tested (acceptance criterion ± 10%). Care should be taken to limit the number of freeze-thaw cycles. Specimens were shown to withstand 3 freeze-thaw cycles when stored at -20°C.

On-Board Stabilitv

Calibration Curve Stability: A stored calibration was effective up to 84 days based on supporting data. Curve stability may depend on individual laboratory performance.

Reagent on-board stability: Reagents were effective when stored after transfer to analyzer specific reagent containers for up to at least 84 days based on supporting data. In-use stability of calibrator and controls was also demonstrated.

Accelerated OPEN stability of calibrators and controls:

Calibrators and controls were shown to be stable OPEN in accelerated stability at 37℃ for seven (7) days. Once opened vials may be stored at 2-8℃ for 12 months.

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

As summarized above, the ARK Gabapentin Assay, the ARK Gabapentin Calibrator and the ARK Gabapentin Control are substantially equivalent to the ARK™ Topiramate Assay system. The ARK Gabapentin Assay system was shown to be safe and effective for its intended use based on performance studies.

ARK Diagnostics, Inc. – 510(k) Summary ARK Gabapentin Assay

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Image /page/15/Picture/1 description: The image shows the seal of the Department of Health & Human Services USA. The seal features a stylized eagle with three wavy lines emanating from its body, representing the department's mission to protect and promote the health and well-being of Americans. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" is arranged in a circular pattern around the eagle.

Food and Drug Administration 10905 New Hampshire Avenue Document Mail Center - WO66-0609 Silver Spring. MD 20993-0002

ARK Diagnostics, Inc. c/o Johnny Valdez President 1190 Bordeaux Drive Sunnyvale, CA 94089

NOV 2 3 2010

Re: K101574

Trade/Device Name: ARKTM Gabapentin Assay, ARK™ Gabapentin Calibrator, and ARK™ Gabapentin Control Regulation Number: 21 CFR 862.3350 Regulation Name: Diphenylhydantoin Test System. Regulatory Class: Class II Product Codes: OTF, DLJ. LAS Dated: November 15, 2010 Received: November 16, 2010

Dear Mr. Valdez,

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.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21, Code of Federal Regulations (CFR), Parts 800 to 895. 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); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

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Page 2 -

If you desire specific advice for your device on our labeling regulation (21 CFR Parts 801 and 809), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 796-5450. 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 Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours,

C.C.

Courtney Harper, Ph.D. Director Division of Chemistry and Toxicology Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Indication for Use

K101574/

510(K) Number (if known):

NOV 2 3 2010

ARK™ Gabapentin Assay ARKTM Gabapentin Calibrator ARKTM Gabapentin Control

Indications for Use:

Device Name:

The ARK™ Gabapentin Assay is a homogeneous enzyme immunoassay intended for the quantitative determination of gabapentin in human serum or plasma on automated clinical chemistry analyzers.

Gabapentin concentrations can be used as an aid in management of patients treated with gabapentin.

The ARK™ Gabapentin Calibrator is intended for use in calibration of the ARK Gabapentin Assay.

The ARK™ Gabapentin Control is intended for use in quality control of the ARK Gabapentin Assay.

Prescription Use X (21 CFR Part 801 Subpart D) And/Or

Over the Counter Use _ (21 CFR Part 801 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE; CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Device Evaluation and Safety (OVD)

Carol C. Benson

Division Sign-Off Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K101574

ARK Gabapentin Assay - Indications/Intended Use ARK Diagnostics, Inc.

Regulation Number and Section

§ 862.3350 Diphenylhydantoin test system.

(a)
Identification. A diphenylhydantoin test system is a device intended to measure diphenylhydantoin, an antiepileptic drug, in human specimens. Measurements obtained by this device are used in the diagnosis and treatment of diphenylhydantoin overdose and in monitoring levels of diphenylhydantoin to ensure appropriate therapy.(b)
Classification. Class II.