ThromboTek PSe is intended for the quantitative determination of functional Protein S activity, such as when identifying inherited or acquired Protein S deficiency.

Device Description

ThromboTek PSe is a tissue factor pathway based clotting assay. The assay activator is a lyophilized preparation incorporating rabbit thromboplastin, calcium, buffer, and stabilizers. The remaining components of the assay are lyophilized activated Protein C, lyophilized human plasma depleted of Protein S, Imidazole buffered saline for use as a plasma diluent, and deionized water containing a preservative for reconstitution of the lyophilized components.

AI/ML Overview

Here's a summary of the acceptance criteria and study details for the ThromboTek PSe assay, based on the provided K082631 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

Feature	Acceptance Criteria (Implied)	Reported Device Performance
Precision	Low %CV for both normal and abnormal plasma samples.	Normal Plasma: Repeatability 4.9% CV, Total 5.7% CV
		Abnormal Plasma: Repeatability 7.8% CV, Total 9.2% CV
Linearity	Linear across the clinically relevant range.	Linear from 10% Protein S to 156% Protein S (maximum tested).
Analytical Sensitivity	Low limit of detection for Protein S activity.	1% Protein S.
Interferences	Minimal impact from common interferants at specified concentrations (e.g., <10% shift in recovered value).	Hemolysis (Hemoglobin): Tolerated up to 500 mg/dL
		Icterus (Unconjugated Bilirubin): Tolerated up to 20 mg/dL
		Lipemia (IntraLipid®): Tolerated up to 2,000 mg triglyceride/dL
		Heparin: Tolerated up to 1.0 U/mL (Tested up to 2.0 U/mL)
Normal Reference Range	Clinically reasonable range for healthy individuals.	All Donors (n=120): Mean 120% PS, Range 47% - 193% PS
		Males only (n=35): Mean 135% PS, Range 62% - 209% PS
		Females only (n=85): Mean 114% PS, Range 45% - 183% PS
Method Comparison	Strong correlation with a legally marketed predicate device.	Correlation Coefficient: 0.895 (95% CI, 0.875-0.912)
		Coefficient of Determination: 0.801
		Slope: 1.71, Intercept: -8.59
Reconstituted Stability	Specified stability period at various storage conditions.	2-8°C: 24 hours
		Room temperature (23-25°C): 8 hours
Accelerated Stability	Predicted expiry dating based on heat stress.	Predicted Expiry: 2 years when stored at 2-8°C.

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

Precision:
- Sample Size: Not explicitly stated as individual samples. Studies used a "normal plasma" and an "abnormal plasma" across three lots of the device over 20 days (two runs per day).
- Data Provenance: Not specified, but likely internal laboratory data (retrospective/concurrent testing).
Linearity:
- Sample Size: Not explicitly stated. Three lots of the device were used.
- Data Provenance: Not specified, likely internal laboratory data.
Analytical Sensitivity:
- Sample Size: Replicate measurement of "IBS alone" (presumably a blank or very low concentration sample) for three lots of the device. The number of replicates is not specified.
- Data Provenance: Not specified, likely internal laboratory data.
Interferences:
- Sample Size: "Pooled normal plasma" spiked with interferants, and a dilution series prepared. Multiple lots of the device were used. The number of individual samples or replicates is not specified.
- Data Provenance: Not specified, likely internal laboratory data.
Normal Reference Range:
- Sample Size: One hundred twenty (120) healthy donors.
- Data Provenance: Not specified, but generally, such studies involve prospective collection of samples from healthy individuals.
Method Comparison:
- Sample Size: One hundred seventy-four (174) patient samples.
- Data Provenance: Collected from "two sites." Given the clinical nature of patient samples, this refers to prospective or retrospective patient samples from those sites. The country of origin is not specified but presumed to be US given the FDA submission.
Reconstituted Stability:
- Sample Size: Two control plasmas. Three lots of the device were assessed.
- Data Provenance: Not specified, likely internal laboratory data.
Accelerated Stability:
- Sample Size: Three lots of control plasmas. One lot of the ThromboTek PSe lyophilized components was stressed.
- Data Provenance: Not specified, likely internal laboratory data.

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

This device (ThromboTek PSe) is an in vitro diagnostic (IVD) assay for quantitative determination of Protein S activity. The concept of "ground truth" established by experts in the context of this device differs from image-based or clinical diagnosis AI algorithms. For this type of IVD, the "ground truth" is typically established by:

Analytical methods and reference standards: For linearity, sensitivity, precision, and interference, the "ground truth" is the known concentration, expected performance, or absence/presence of interferants as precisely measured and controlled in the laboratory.
Reference materials/standards: For the normal reference range, the results are compared against universally accepted ranges for healthy populations or specific reference materials (e.g., SSC/ISTH Secondary Coagulation Standard Lot #3 from NIBSC was used for calibration).
Predicate device results: For method comparison, the results from the legally marketed predicate device (StaClot® Protein S) serve as the comparative "ground truth."

Therefore, there were no "experts" in the sense of radiologists or pathologists providing consensus diagnoses. Instead, the ground truth was based on established laboratory methods, validated reference materials, and comparison with an approved predicate device.

4. Adjudication Method for the Test Set

Not applicable for this type of IVD assay. Adjudication methods like 2+1 or 3+1 are typically used in studies involving subjective interpretation (e.g., imaging where multiple readers independently assess findings, and discrepancies are resolved). For quantitative assays, the results are numerical and are compared against reference values, other assay results, or statistical criteria.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This type of study is relevant for devices that assist human readers in tasks like image interpretation. The ThromboTek PSe is a standalone diagnostic assay, not an AI-assisted tool for human interpretation.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, the ThromboTek PSe is a standalone in vitro diagnostic device. All performance characteristics (precision, linearity, sensitivity, interference, normal range determination, method comparison, and stability) were evaluated for the assay itself, without a human-in-the-loop component for interpretation or diagnosis. The device provides a quantitative output (Protein S activity percentage).

7. The Type of Ground Truth Used

The ground truth used for performance evaluation was a combination of:

Reference Standards/Known Concentrations: For analytical sensitivity, linearity, and precision, the "ground truth" was derived from precisely prepared samples with known (or expected) Protein S concentrations or matrix compositions. Calibration was performed using the SSC/ISTH Secondary Coagulation Standard Lot #3.
Assay results from a predicate device: For method comparison, the results from the StaClot® Protein S assay served as the comparative ground truth.
Clinically Defined Populations: For normal reference range, the ground truth was derived from the Protein S activity measured in a cohort of healthy donors.

8. The Sample Size for the Training Set

This filing describes a traditional IVD assay, not a machine learning or AI-driven device. Therefore, there is no "training set" in the typical machine learning sense. The device's performance is based on its chemical/biological reaction principles and direct measurement, not on learning from a dataset.

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

Since there is no "training set" for an AI algorithm, this question is not applicable. The device's operational principles are pre-defined by its reagents and methodology, not learned from data.

Summary

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K082631

DEC 1 7 2008

Section 7: 510(k) Summary

510(k) Substantial Equivalence Determination Decision Summary Assay Only Template

This summary of 510(k) safety and effectiveness is being submitted in accordance with the requirements of the Safe Medical Device Act of 1990 and 21 CFR 807.92.

A. 510(k) Number

B. Date and Purpose for Submission September 9, 2008
To obtain clearance for the ThromboTek PSe assay, a functional (clotting) assay for the determination of Protein S activity in human plasma.
ن Measurand Protein S
D. Type of Test Quantitative factor determination, clotting assay.
Applicant E. r2 Diagnostics, Inc 1801 Commerce Drive South Bend, IN 46628
F. Proprietary and Established Name ThromboTek PSe
G. Regulatory Information 1. Regulation Section 864.7290, Factor Deficiency Test
- 2. Classification II
- 1. Product Code GGP
- 1. Panel Hematology

Page_1 Section

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H. Intended Use
- 1. Intended Use

ThromboTek PSe is intended for the quantitative determination of functional Protein S activity in human plasma.

2. Indication(s) for Use

ThromboTek PSe is intended for the quantitative determination of functional Protein S activity, such as when identifying inherited or acquired Protein S deficiency.

1. Special conditions for use statement(s) Not applicable
1. Special instrument requirements Not applicable

I. Device Description

J. Substantial Equivalence Information

1. Predicate device name(s) StaClot® Protein S
1. Predicate device 510(k) number K913424

Section 7, Page 2

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2. Comparison with predicate

Table 7-1: Comparison of submitted device (ThromboTek PSe) topredicate device (StaClot Protein S)
Similarities
Item	Submitted Device	Predicate Device
Intended use	Quantitative determination offunction Protein S activity.	Quantitative determination offunction Protein S activity.
Patient sample	Citrated human plasma	Citrated human plasma
Measurement principle	Protein S is rate limiting in aclotting reaction.	Protein S is rate limiting in aclotting reaction.
Format of assay components	Lyophilized activator,lyophilized aPC, lyophilizedProtein S deficient plasma	Lyophilized activator,lyophilized aPC, lyophilizedProtein S deficient plasma
Analyte	Protein S activity	Protein S activity
Differences
Item	Submitted Device	Predicate Device
Assay linearity	10%-156% (max tested)	10%-105% (per DirectionalInsert)
Reconstituted Stability	RT: 8 hrs2-8C: 24 hrs	RT: 4 hrs2-8C: 4 hrs(per Directional Insert)
Analytical Sensitivity	1%	8%(per Directional Insert)
Remaining componentsnecessary to run the assay	Imidazole buffered saline andreconstitution solution (water)are provided in kit.	Owen-Koller buffer and calciumchloride are purchasedseparately, and reconstitutiongrade water is provided by user

K. Standard/Guidance Documents Referenced (if applicable) Not applicable

L. Test Principle

Thromboplastin is a tissue-derived complex incorporating the protein Tissue Factor (TF) associated with lipid vesicles. When Thromboplastins are added to plasmas the endogenous Factor VII (FVII) or activated Factor VII (FVIIa) in the plasma complex with the Tissue Factor and lipid vesicle in the presence of calcium, which then activates the Tissue Factor pathway of blood coagulation. This TF/FVIIa complex activates Factor X (FX) to activated FX (FXa). Factor Xa complexes with activated Factor V (FVa) on a lipid surface in the presence of calcium to form the prothrombinase complex. The prothrombinase complex activates Prothrombin to Thrombin. Thrombin, without any cofactors or ion dependency, will cleave Fibrinogen to Fibrin, leading to formation of a solid clot.

Activated Protein C (aPC) in the presence of its cofactor Protein S (PS) degrades activated Factor Va (and VIIIa), reducing the catalytic efficiency of the prothrombinase complex. When the assay conditions are chosen such that an excess of aPC is present and the concentration of Protein S in the patient sample is rate limiting, the time to clot of the patient plasma becomes proportional to the

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concentration of the patient PS and can be used to quantify the PS activity in the sample.

M. Performance Characteristics (if/when applicable)
Performance evaluation of the ThromboTek PSe kit included studies of precision, linearity, analytical sensitivity, common interferants, normal range, correlation with the StaClot® kit, and reconstituted and accelerated stability. The method, samples, reagents, and results of each study are described in detail in section 23, Performance Data. No bench (section 20), animal (section 21), or clinical (section 22) testing was required. Summaries of the studies are:

Precision: Precision estimates of three lots of ThromboTek PSe were determined in a two run per day, twenty day exercise using a normal plasma and an abnormal plasma as described in the CLSI guideline EP5-A2 (7). The average precision results as %CV were:

Plasma	Repeatability	Total
Normal	4.9%	5.7%
Abnormal	7.8%	9.2%

Linearity: Linearity studies of three lots of ThromboTek PSe were determined on a Stago ST4 analyzer. The ThromboTek PSe assay was linear from 10% Protein S to the maximum tested concentration of 156% Protein S.

Analytical Sensitivity: The lower limit of detection for three lots of ThromboTek PSe were determined by replicate measurement of IBS alone as the sample on an AMAX 200 analyzer in mechanical mode, and the % PS activity was calculated from the sum of the mean and 3 standard deviations. The lower limit of detection of the assay was 1% PS.

Interferences: Interference studies of multiple lots of ThromboTek PSe were determined on an AMAX 200 analyzer in mechanical mode. Interferant was spiked into pooled normal plasma and a dilution series prepared. The maximum concentration tolerated in the assay was defined as the highest concentration of interferant wherein any consistent shift relative to the recovered value of the base PNP was less than 10%. The maximum concentrations were:

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Interferantclass	Addedinterferant	Maximumconcentration tested	Maximumtoleratedconcentration
Hemolysis	Hemoglobin	500 mg/dL	500 mg/dL
Icterus	Unconjugatedbilirubin	20 mg/dL	20 mg/dL
Lipemia	IntraLipid®	2,000 mgtriglyceride/dL	2,000 mgtriglyceride/dL
Heparin	Heparin	2.0 Unit/mL	1.0 U/mL

Normal Reference Range:

In a representative study one hundred twenty healthy donors were analyzed for Protein S activity with each of three lots of ThromboTek PSe on an AMAX 200 analyzer in mechanical mode. Assay calibration was performed using the SSC/ISTH Secondary Coagulation Standard Lot #3 available from NIBSC. The geometric means and standard deviations were calculated, and the ranges were calculated as the mean +/- 2 standard deviations. The results were:

Donors	Number	Mean % PS	Range %PS
All	120	120%	47% - 193%
Males only	35	135%	62% - 209%
Females only	85	114%	45% - 183%

Method Comparison:

A total of one hundred seventy-four patient samples were assayed for Protein S activity with multiple lots of ThromboTek PSe and two lots of another commercially available Protein S activity assay. The data was collected in two sites, one using an AMAX 200 analyzer and the other a STart4 analyzer. As determined by Kruskal-Wallis analysis the data was pooled and then further analyzed by linear regression. The correlation coefficient was 0.895 (95% CI, 0.875-0.912) and the coefficient of determination was 0.801, with a slope and intercept of 1.71 and -8.59 respectively.

Reconstituted Stability

The reconstituted stability of the ThromboTek PSe kit was assessed by longitudinal studies of three lots. The recoveries of two control plasmas were assessed at the initial reconstitution of each kit, and thereafter at periodic time points. The kit components were stored capped when not in use and freshly reconstituted control plasmas were prepared at each time point. With criteria of an age-related trend and a maximum shift of twice the precision CV, the predicted reconstituted stability of the ThromboTek PSe kit is 24 hours when stored at 2-8°C and 8 hours when stored at room temperature (23-25°C).

Accelerated Stability:

Expiry dating was predicted by a heat stress accelerated stability study of one lot of ThromboTek PSe. The study used two different sets of the kit lyophilized components, with one set stressed at 37℃ for up to 25 days and the second set at

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45℃ for up to 7 days. Thereafter three lots of control plasmas were assayed with the unstressed and stressed components, and assessed for any age-related shift in recoveries. With criteria of an age-related trend and a maximum shift of 10%, the predicted expiry dating of the ThromboTek PSe kit is 2 years when stored at 2-8°C.

Proposed labeling N.

The labeling is sufficient and satisfies the requirements of 21 CFR Part 809.10.

The label text for the directional insert and for the vial and box labels is included in section 15.

O. Conclusion

The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

Other Supportive Information P.

Q. Administrative Information

Applicant contact information Marc Goldford, Director of Research and Development r2 Diagnostics, Inc. 1801 Commerce Drive South Bend, IN 46628 Voice: 574-288-4377 Fax: 574-288-2272 Email: marc@r2diagnostics.com

Section 7, Page 6

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/6/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is circular and contains the words "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" around the perimeter. Inside the circle is an abstract image of an eagle.

Public Health Service

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

R2 Diagnostics, Inc. C/o Marc D. Goldford 1801 Commerce Drive South Bend, Indiana 46628

Re: K082631

Trade/Device Name: Thrombo Tek PSe Regulation Number: 21 CFR 864.7290 Regulation Name: Factor Deficiency Test Regulatory Class: Class II Product Code: GGP Dated: November 19, 2008 Received: November 20, 2008

DEC 1 7 2008

Dear Mr. Goldford:

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

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Page 2 – Mr. Goldford

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), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at 240-276-0450. Also, please note the regulation entitled. "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding postmarket surveillance, please contact CDRH's Office of Surveillance and Biometric's (OSB's) Division of Postmarket Surveillance at 240-276-3474. For questions regarding the reporting of device adverse events (Medical Device Reporting (MDR)), please contact the Division of Surveillance Systems at 240-276-3464. 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 (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours.

Josephine Bautista
Marian Chan, PhD

Acting Division Director Division of Immunology and Hematology Devices Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

Enclosure

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Section 6: Indication for Use Statement

Indication for Use

510(k) Number (if known):

K082631

Device Name: ThromboTek PSe

Indication For Use: r2 Diagnostics' ThromboTek PSe Protein S assay is used for the quantitative determination of functional Protein S activity in human plasma.

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

Josephine Bautista

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

510(k) K082163|

Section

Regulation Number and Section

§ 864.7290 Factor deficiency test.

(a)
Identification. A factor deficiency test is a device used to diagnose specific coagulation defects, to monitor certain types of therapy, to detect coagulation inhibitors, and to detect a carrier state (a person carrying both a recessive gene for a coagulation factor deficiency such as hemophilia and the corresponding normal gene).(b)
Classification. Class II (performance standards).