The INNOFLUOR® Phenobarbital Assay System is an in vitro diagnostic device intended for the quantitative determination of total Phenobarbital in serum for therapeutic drug monitoring by fluorescence polarization immunoassay. The assay system is for use on the Abbott TDx® or the TDxFLx® analyzer.

The INNOFLUOR® Phenobarbital Reagent Set is intended for the quantitative determination of total phenobarbital in serum for therapeutic drug monitoring. The reagent set is intended for use in the INNOFLUOR® Phenobarbital Assay System.

The INNOFLUOR® Phenobarbital Calibrator Set is intended for use in the calibration of the INNOFLUOR® Phenobarbital Assay System.

Device Description

The INNOFLUOR® Phenobarbital Assay System is an in vitro diagnostic device used to monitor serum levels of the therapeutic, anticonvulsant drug, phenobarbital. It is a fluorescence polarization immunoassay based on the competitive binding principle. The system consists of two products: the INNOFLUOR® Phenobarbital Reagent Set (containing Phenobarbital Antibody, Phenobarbital fluorescein TRACER, and PRE TREATMENT BUFFER) and the INNOFLUOR® Phenobarbital Calibrator Set (containing human serum with added phenobarbital at various concentrations). The system is for use on the Abbott TDx® or TDxFLx® analyzer.

AI/ML Overview

The provided text is a 510(k) premarket notification for the INNOFLUOR® Phenobarbital Assay System. It describes the device, its intended use, and provides a summary of the components and principles. However, it does not contain the detailed study information or acceptance criteria and performance data that would typically be found in a clinical study report or a more comprehensive technical document.

Therefore, many of the requested items cannot be definitively answered from the provided text. I will provide information based on what is available and indicate when information is missing.

Acceptance Criteria and Device Performance Study (as much as can be inferred/extracted)

1. Table of acceptance criteria and the reported device performance:

The document does not explicitly state quantitative acceptance criteria or present a table of device performance against such criteria. The closest information pertains to demonstrating "quantitative recovery" and "accuracy" through comparison with other methods/materials.

Criterion Type	Acceptance Criterion (Inferred/Missing)	Reported Device Performance (Inferred/Extracted)
Accuracy (Calibrators)	Not explicitly stated. Likely related to quantitative recovery within a certain percentage of expected values.	Calibrators are prepared gravimetrically, and their accuracy is verified using the United States Pharmacopoeia Reference Standard for Phenobarbital. "Data from these experiments demonstrate quantitative recovery, i.e., accuracy, of the INNOFLUOR® Phenobarbital Calibrator Set." (Representative data is mentioned as being in the package insert, but not included here).
Accuracy (Recovery Samples)	Not explicitly stated. Likely related to quantitative recovery within a certain percentage of expected values.	Recovery samples are prepared gravimetrically (using USP Phenobarbital analyte) and then analyzed by the INNOFLUOR® system and compared to results obtained from the Abbott Phenobarbital FPIA. "Multiple lots... similarly prepared and assayed using the INNOFLUOR® Phenobarbital Assay System. Data from these experiments demonstrate quantitative recovery, i.e., accuracy, of the INNOFLUOR® Phenobarbital Calibrator Set..."
Accuracy (Control Materials & Proficiency Testing)	Not explicitly stated. Likely agreement with published results from other methods.	"Data collected on commercially available control materials and proficiency testing samples confirms accuracy of the results provided by the INNOFLUOR® Phenobarbital Assay System, as do results obtained by comparison of patient samples with a reference assay."
Precision/Reproducibility	Not explicitly stated.	Not mentioned in the provided text.
Linearity/Range	Not explicitly stated.	The calibrators cover the range of 0.0 to 80.0 µg/mL. Recovery samples are prepared across a range of 0.0 to 80.0 µg/mL.
Interference	Not explicitly stated.	The surfactant in the Pre-treatment Buffer is selected to "prevent interference by endogenous sample matrix constituents, such as lipids, proteins, hemoglobin and bilirubin." However, specific performance data regarding interference is not provided.

2. Sample size used for the test set and the data provenance:

Sample Size for Test Set: Not explicitly stated. The text refers to "recovery samples" prepared at various concentrations (0.0, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 40.0, 60.0 and 80.0 ug/mL) and "multiple lots" of commercially available control materials and proficiency testing samples. It also mentions "patient samples." Specific numbers are absent.
Data Provenance (e.g., country of origin of the data, retrospective or prospective):
- Calibrators and Recovery Samples: These are laboratory-prepared samples using human serum (phenobarbital-free normal human serum pool). The origin of this human serum is not specified, but the manufacturing entity (OXIS International, Inc.) is based in Portland, Oregon, USA.
- Control Materials and Proficiency Testing Samples: These are described as "commercially available," implying they are external, but their specific origin is not detailed.
- Patient Samples: Mentioned for comparison with a reference assay, but no details on their number or origin.
- The studies appear to be laboratory-based evaluations of the assay's performance rather than clinical trials with patient cohorts, making the retrospective/prospective distinction less applicable in its typical sense.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

This information is not applicable and therefore not provided in the document. The "ground truth" for the calibrators and recovery samples is established by gravimetric preparation with a USP Reference Standard. For control materials and proficiency samples, the "ground truth" is implied to be values published or established by the manufacturers of those materials, often through multi-method analysis, not by individual experts or review panels in the medical imaging sense.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

Not applicable as the "ground truth" is established through analytical methods and reference standards, not through expert adjudication of medical cases.

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 is an in-vitro diagnostic assay for quantitative determination of a drug in serum, not an imaging device or AI-assisted diagnostic tool that involves human "readers" or "interpreters" in the clinical imaging sense.

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

This is a standalone assay system. The performance described is that of the assay system itself using the Abbott TDx® or TDxFLx® analyzer. There isn't an "algorithm only" component separate from the reagents and analyzer interaction. Human intervention is required for sample preparation, loading, and interpreting the quantitative result displayed by the analyzer. It's not a "human-in-the-loop" application in the AI sense, but rather a standard laboratory assay where human operators execute the procedure.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

Analytical Ground Truth:
- Calibrators and Recovery Samples: Gravimetric preparation by spiking known concentrations of high-purity phenobarbital analyte (United States Pharmacopoeia Reference Standard for Phenobarbital) into phenobarbital-free normal human serum.
- Control Materials and Proficiency Testing Samples: Published values associated with commercially available materials, often established through round-robin testing or analysis by multiple reference methods.
- Patient Samples: Comparison against a "reference assay" (Abbott Phenobarbital FPIA is mentioned as a method used for verification, implying it serves as a comparative reference).

8. The sample size for the training set:

Not explicitly defined within the context of a "training set" for machine learning. This is a traditional immunoassay system. The development and optimization of the antibody and tracer would involve extensive laboratory work, but not in the sense of a discrete "training set" for an algorithm. The "training" for such a system involves selecting optimal reagents and optimizing assay parameters.

9. How the ground truth for the training set was established:

As above, not applicable in the machine learning "training set" context. The "ground truth" for developing and optimizing the assay components (antibody selection, tracer purification, buffer formulation) relies on analytical chemistry principles, experimental validation of binding characteristics, and empirical testing to achieve desired assay performance characteristics (e.g., sensitivity, specificity, dynamic range). The "ground truth" during this development phase would be based on known concentrations of phenobarbital and the chemical and immunological properties of the reagents.

Summary

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972330

DEVICE NARRATIVE

JUL 1 4 1997

IDENTIFICATION OF SUBMITTER

Submitter: OXIS International, Inc. 6040 N Cutter Circle, Suite 317 Portland, OR 97217-3935

Contact Person: Lynda M. Taylor Vice President, Technical Operations and Regulatory Affairs

Date Prepared: April 25, 1997

IDENTIFICATION OF DEVICE

Trade Name: INNOFLUOR® Phenobarbital Assay System, which consists of two products that are packaged and sold separately: the INNOFLUOR® Phenobarbital Reagent Set and the INNOFLUOR® Phenobarbital Calibrator Set.

Common or Usual Name: Phenobarbital Fluorescence Polarization Immunoassay

Classification Name: Fluorescence Polarization Immunoassay, Phenobarbital

IDENTIFICATION OF EQUIVALENT DEVICE

Substantial equivalence has been demonstrated between the INNOFLUOR® Phenobarbital Assay System. Modified, the INNOFLUOR® Phenobarbital Assay System, Existing and the Abbott Phenobarbital Assay.

DEVICE DESCRIPTION

THE INNOFLUOR PHENOBARBITAL ASSAY SYSTEM:

The INNOFLUOR® Phenobarbital Assay System is an in vitro diagnostic device used to monitor serum levels of the therapeutic, anticonvulsant drug, phenobarbital.

Phenobarbital is a barbiturate that has been used extensively as an anticonvulsant since 1912 (1.2). It is generally administered to epileptic patients in oral doses, often in conjunction with other anticonvulsant drugs. Oral absorption of phenobarbital is complete but slow, with peak plasma concentration reached several hours after intake.(1) Approximately 50% of the drug is bound to plasma proteins, with binding to a similar extent in tissue.(1) After dosing, 25-50% is excreted unchanged in the urine.(3) The remainder is metabolized almost exclusively in the liver to inactive metabolites, mainly the parahydroxyphenyl and N-glucoside derivatives.(1,4,5)

Monitoring serum concentrations of phenobarbital has been recommended for effective patient therapy because of the narrow therapeutic index and wide interindividual variability in the rate of metabolism and clearance of phenobarbital.(6.7) Immunoassays using a fluorescence polarization technique for phenobarbital have been published.(8,9) (See Attachment C, the INNOFLUOR® Phenobarbital Assay System package insert, Bibliography, for references.)

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The INNOFLUOR® Phenobarbital Assay System consists of the following two products which are packaged and sold separately, but are referred to collectively, in associated product labeling and in this 510(k) Notification as the INNOFLUOR® Phenobarbital Assay System. Neither the reagent set nor the calibrator set are intended to be used separately nor in combination with any other manufacturer's reagent or calibrator sets.

INNOFLUOR® Phenobarbital Reagent Set, Catalog No. 11013, sufficient for 100 tests, 1. consists of the following reagents:
- < 5% Phenobarbital ANTIBODY (Mouse) in buffer, containing protein as a. stabilizer and < 0.1% sodium azide as preservative (3 mL). Cap label "A."
- < 0.1% Phenobarbital fluorescein TRACER in buffer, containing a surfactant, b. protein as stabilizer and < 0.1% sodium azide as preservative (3 mL). Cap label "T"
- PRE TREATMENT BUFFER, containing a surfactant and < 0.1% sodium azide C. as preservative (3 mL). Cap label "B."
INNOFLUOR® Phenobarbital Calibrator Set, Catalog No. 41018, sufficient for four 2. duplicate calibration curves, consists of six vials, labeled A, B, C, D, E and F, each containing 1 mL of human serum and < 0.1 % sodium azide as preservative with 0.0. 5.0, 10.0, 20.0, 40.0 and 80.0 ug/mL of added phenobarbital, respectively.

PRINCIPLES OF THE INNOFLUOR® PHENOBARBITAL ASSAY SYSTEM PROCEDURE:

The INNOFLUOR® Phenobarbital Assay System, a fluorescence polarization immunoassay, is based on the competitive binding principle. Phenobarbital antigen in a sample competes with fluorescein - labeled phenobarbital for a fixed number of antibody binding sites. When linearly polarized light is used to excite the fluorescein - labeled phenobarbital, which is small and rotates rapidly in solution, emitted light is significantly depolarized. When fluorescein - labeled phenobarbital is bound to antibody, rotation is slowed and linearly polarized excitation light stays highly polarized upon emission. Increased amounts of unlabeled phenobarbital in a sample will result in decreased binding of fluorescein - labeled phenobarbital by antibody, and decreased polarization of emitted light from the sample. The concentration of phenobarbital in an unknown sample can be determined by comparing the polarization value of the unknown sample against polarization values from a calibration curve established on the Abbott TDx® or TDxFLx® analvzer.

The INNOFLUOR® Phenobarbital Reagent Set and Calibrator Set are used together to generate the calibration curve on the TDx® or TDxFLx® analyzer. The calibration curve must be established prior to assaying unknown samples. Prior to performing the calibration procedure, the correct analyzer operating parameters must be set by following the instructions provided in the Product Insert Supplement, which is included with every INNOFLUOR® Phenobarbital Reagent Set.

Phenobarbital controls are required to monitor assay performance and the quality and stability of the calibration curve. Appropriate statistical methods should be used to evaluate trends in control values and establish ranges of acceptability. Following calibration, at least two levels

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of phenobarbital controls must be assayed to verify the acceptability of the calibration. At least one level of control material should be included with each carousel containing patient samples. At least two levels of control material must be assayed each 24 hour period of time during which patient samples are assayed.

SUMMARY OF INNOFLUOR® PHENOBARBITAL REAGENT SET:

Phenobarbital Mouse (Monoclonal) Antibody

The antibody contained in the INNOFLUOR® Phenobarbital Assay System was selected by screening commercially available phenobarbital antibodies for characteristics that would provide optimal performance in an FPIA test format. The antibody selected for use in the INNOFLUOR® Phenobarbital Reagent Set is a commercially available mouse monoclonal antibody against phenobarbital. The antibody is purchased, and exact details describing how the antibody is raised are proprietary and are not available to OXIS. A Product Specification Sheet, provided by the vendor, includes the following information:

Description:	Murine Monoclonal anti-Phenobarbital
Name:	PbAs17
Ig Concentration:	10.0 mg/mL
Isotope:	IgG1,K
Titer:	1:1.2 x $10^5$
Product Form:	Ascites Fluid with 0.1% Sodium Azide added as preservative

Phenobarbital-fluorescein Tracer (PB-V:FAMCO-E)

The phenobarbital tracer selected for use in the INNOFLUOR® Phenobarbital Assay System is a conjugation of phenobarbital to fluorescein. The conjugate is purified by low pressure C18 chromatography, coupled with thin layer chromatography (TLC) on silica gel. The tracer purity is established by analytical TLC and by binding of the mouse antibody selected for use in the INNOFLUOR® Phenobarbital Assay System.

Phenobarbital Pre-treatment Buffer Reagent

The Phenobarbital Pre-treatment Buffer Reagent contains surfactant in a buffer solution. The surfactant was selected based on its ability to prevent interference by endogenous sample matrix constituents, such as lipids, proteins, hemoglobin and bilirubin.

SUMMARY OF INNOFLUOR PHENOBARBITAL CALIBRATOR SET:

The INNOFLUOR® Phenobarbital Calibrators are prepared gravimetrically by spiking a stock solution of high purity phenobarbital analyte into a phenobarbital-free normal human serum pool at concentrations covering the calibration range of the assay, i.e., 0.0, 5.0, 10.0, 20.0, 40.0 and 80.0 µg/mL.

The reference material used to verify the accuracy of the calibrators is the United States Pharmacopoeia Reference Standard for Phenobarbital, Catalog No. 28900. Recovery samples are prepared gravimetrically by diluting a stock solution made from USP Phenobarbital analyte into a phenobarbital free normal human serum pool at concentrations

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across the calibration range of the assay, i.e., 0.0, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 40.0, 60.0 and 80.0 ug/mL. Concentrations of the recovery samples are verified by analysis of the samples using Abbott Phenobarbital FPIA. Multiple lots of the USP Phenobarbital recovery samples are similarly prepared and assayed using the INNOFLUOR® Phenobarbital Assay System. Data from these experiments demonstrate quantitative recovery, i.e., accuracy, of the INNOFLUOR® Phenobarbital Calibrator Set (representative data is provided in the INNOFLUOR® Phenobarbital Assay System package insert).

Additional accuracy verification is performed by assaying multiple lots of commercially available control materials and proficiency testing samples using the INNOFLUOR® Phenobarbital Assay System and comparing test results with results published for the samples measured using multiple commercially available test methods. Data collected on commercially available control materials and proficiency testing samples confirms accuracy of the results provided by the INNOFLUOR® Phenobarbital Assay System, as do results obtained by comparison of patient samples with a reference assay.

STATEMENT OF INTENDED USE

The INNOFLUOR® Phenobarbital Reagent Set and the INNOFLUOR® Phenobarbital Calibrator Set are packaged and sold separately, but are referred to collectively, in all associated product labeling, as the INNOFLUOR® Phenobarbital Assay System.

The INNOFLUOR® Phenobarbital Calibrator Set is intended for use in the calibration of the INNOFLUOR® Phenobarbital Assay System.

The INNOFLUOR® Phenobarbital Reagent Set and Calibrator Set are used together to generate the calibration curve on the TDx®/TDxFLx® analyzer. The calibration curve must be established prior to assaying unknown samples. Prior to performing the calibration procedure. the correct analyzer operating parameters must be set by following the instructions provided in the Product Insert Supplement, which is included with every INNOFLUOR® Phenobarbital Reagent Set.

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Image /page/4/Picture/1 description: The image shows the seal of the Department of Health & Human Services USA. The seal features a stylized caduceus, a symbol often associated with medicine and healthcare, with three intertwined strands. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" are arranged in a circular pattern around the caduceus.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Lynda M. Taylor Vice President, Technical Operations OXIS International, Inc. 6040 N. Cutter Circle, Suite 317 Portland, Oregon 97217-3935

JUL 1 4 1097

K972330 Re : INNOFLUOR™ Phenobarbital Reagent Set Requlatory Class: II Product Code: LGQ Dated: June 20, 1997 Received: June 23, 1997

Dear Ms. Taylor:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). You may, therefore, market the device, subject to the qeneral controls provisions The general controls provisions of the Act 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 (Premarket Approval), it may be subject to such additional controls. Existing major requlations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP requlation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal Laws or Requlations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at (770) 488-7655.

This letter will allow you to begin marketing your device as described in your 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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4588. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to
premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".

Sincerely yours,
Steven Sitman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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11972330 510(k) Number (if known):

Device Name: __ INNOFLUOR® Phenobarbital Assay System

Indications For Use:

The INNOFLUOR® Phenobarbital Calibrator Set is intended for use in the calibration of the INNOFLUOR® Phenobarbital Assay System.

The INNOFLUOR® Phenobarbital Reagent Set and Calibrator Set are used together to generate the calibration curve on the TDx@TDxFLx® analyzer. The calibration curve must be established prior to assaying unknown samples. Prior to performing the calibration procedure, the correct analyzer operating parameters must be set by following the instructions provided in the Product Insert Supplement, which is included with every INNOFLUOR® Phenobarbital Reagent Set.

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use V (Per 21 CFR 801.109)

ાવ

Over-The-Counter Use _________________________________________________________________________________________________________________________________________________________

(Optional Format 1-2-96)

(Division Sign-Off)
Division of Clinical Laboratory Devices
510(k) Number 7-9-97

Regulation Number and Section

§ 862.3660 Phenobarbital test system.

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