The NxStage PureFlow SL module is an optional accessory to the NxStage System One that prepares dialysate for use during hemodialysis, as prescribed by the physician.

Device Description

The NxStage PFSL module is an optional accessory to the NxStage System One that is used to treat water for hemodialysis and proportion it with dialysate concentrate to produce dialysate per ANSI/AAMI RD52:2004 and ANSI/AAMI RD62: 2006. The PFSL module consists of the Control Unit (CU), the water Pre-Treatment Unit, the Purification Pack (PAK), and the Dialysate Sack (SAK) with Dialysate Concentrate.

AI/ML Overview

The provided text describes a Special 510(k) submission for a device modification, which primarily focuses on demonstrating substantial equivalence to a predicate device. This type of submission relies on design control requirements and performance testing to ensure the modified device meets design specifications and remains as safe and effective as the original. As such, the information you've requested regarding detailed acceptance criteria, specific study designs (like MRMC or standalone performance), sample sizes for test and training sets, and expert qualifications for ground truth establishment is not typically present in a 510(k) summary for such a modification.

The 510(k) summary focuses on demonstrating that the NxStage PureFlow SL (PFSL) module with modifications is substantially equivalent to the legally marketed predicate device (cleared through K060296).

Here's an analysis based on the provided text:

1. A table of acceptance criteria and the reported device performance

The document does not provide a specific table of acceptance criteria with detailed reported performance metrics. Instead, it states:

"Performance, verification and validation testing was conducted to characterize performance of the proposed PFSL to provide a basis of comparison to the predicate device as all features are not identical. Results of this testing have documented that the proposed PFSL module is substantially equivalent to the predicate device and is suitable for the labeled indications for use."

This indicates that internal performance specifications were met to ensure substantial equivalence, but the specific numerical acceptance criteria and results are not disclosed in this summary. The general acceptance criterion is that the modified device performs comparably to the predicate device and meets its design specifications, preparing dialysate per ANSI/AAMI RD52:2004 and ANSI/AAMI RD62: 2006.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

The document does not specify the sample size used for any test set or the data provenance. The testing mentioned is "Performance, verification and validation testing," which typically refers to bench testing rather than clinical study data.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

This information is not applicable and not provided. The study described is a non-clinical, bench-testing comparison for substantial equivalence, not a clinical study requiring expert-established ground truth.

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

This information is not applicable and not provided. The study described is a non-clinical, bench-testing comparison for substantial equivalence.

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

No, an MRMC comparative effectiveness study was not done. This device is an accessory for hemodialysis, and the evaluation is non-clinical, focusing on technological characteristics and performance rather than human reader interpretation.

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

A "standalone" performance evaluation in the context of an algorithm or AI would not apply here. However, the non-clinical "Performance, verification and validation testing" can be considered a standalone evaluation of the device's functional performance against its design specifications and the predicate device.

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

The "ground truth" for this device modification is its design specifications and compliance with relevant industry standards (ANSI/AAMI RD52:2004 and ANSI/AAMI RD62: 2006) for preparing dialysate. The performance was characterized to demonstrate substantial equivalence to the predicate device.

8. The sample size for the training set

This information is not applicable and not provided. This is not an AI/ML device that requires a training set.

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

This information is not applicable and not provided. This is not an AI/ML device that requires a training set.

In summary:

This 510(k) focuses on a "Special 510(k) Device Modification" which primarily relies on demonstrating compliance with 21 CFR §820.30 Design Control Requirements and conducting performance, verification, and validation (bench) testing to confirm that the modified device remains substantially equivalent to its predicate device. This type of submission does not typically involve the detailed clinical study metrics, expert consensus, or AI-specific evaluation criteria often associated with novel medical devices or AI-powered diagnostics.

Summary

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K0806919
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NxStage Medical, Inc. NxStage PureFlow SL (PFSL) 510(k) Device Modification

This 510(k) Summary is being submitted in accordance with the requirements of the Safe Medical Device Act (SMDA) of 1990. The content contained in this 510(k) summary has been provided in conformance with 21 CFR §807.92

A. Submitter's Information:

Name:	NxStage Medical Inc.
Address:	439 South Union Street, 5th FloorLawrence, MA 01843
FDA EstablishmentOwner/Operator Number:	9045797
Contact Person:	Michael DoyleManager, Regulatory Affairs
Phone:Fax:	(978) 687-4746(978) 687-4750
Manufacturing Site:	Entrada Group/NxStageCarretera Fresnillo A Plateros, KM2Fresnillo, Zacatecas 99059Mexico
FDA EstablishmentRegistration Number:	3006546166
Manufacturing/SterilizationSite:	Steris Isomedix, Inc.1000 S. Sarah PlaceOntario, CA 91761
B. Device Name:
Trade/Proprietary Name:	NxStage PureFlow SL
Common/Usual Name:	Subsystem, proportioning
Classification Name:	Hemodialysis Systems & Accessories
Regulation Number:	876.5820
Product Code:	78 FKR
Device Classification:	Class II
Device Panel:	Gastroenterology/Urology

Special 510(k)

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NxStage Medical, Inc. NxStage PureFlow SL (PFSL) Special 510(k) Device Modification

C. Substantial Equivalence/Predicate Devices:
This submission is a Special 510(k) Device Modification as described in the FDA's Guidance document entitled, #The New 510(k) Paradigm - Alternate Approaches to Demonstrating Substantial Equivalence in Premarket Notifications." In support of this Special 510(k), NxStage has provided certification of compliance to 21 CFR §820.30 Design Control Requirements. Design validation testing was performed to ensure that the NxStage PureFlow SL (PFSL) module with modifications meets design specifications. The NxStage PFSL module with modifications has been compared to the legally marketed predicated device as cleared through K060296 (March 31, 2006) and was found to be substantially equivalent.

D. Device Description/Indications for Use:

Indications for use:

The NxStage PFSL module is an optional accessory to the NxStage System One that prepares dialysate for use during hemodialysis, as prescribed by the physician.

E. Technological Characteristics:

The proposed device has the same technological characteristics and is similar in design and configuration as compared to the predicate device. The proposed device is designed with similar components and features also used in the predicate device.

F. Summary of Non-Clinical Test/Performance Testing - Bench:

NxStage Medical, Inc. believes that the information and data provided in this submission clearly describes the proposed device and demonstrates that the device is adequately designed for the labeled indications for use. Performance, verification and validation testing was conducted to characterize performance of the proposed PFSL to provide a basis of comparison to the predicate device as all features are not identical. Results of this testing have documented that the proposed PFSL module is substantially equivalent to the predicate device and is suitable for the labeled indications for use.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/2/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized eagle with three lines representing its wings. The eagle is enclosed within a circular border, with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" surrounding it.

OCT 15 2008

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

Mr. Michael J. Doyle Manager, Regulatory Affairs NxStage Medical, Inc. 439 South Union Street, 5th Floor LAWRENCE MA 01843

K080919 Re:

Trade/Device Name: NxStage PureFlow SL Regulation Number: 21 CFR §876.5820 Regulation Name: Hemodialysis system and accessories Regulatory Class: II Product Code: FKR Dated: August 12, 2008 Received: August 13, 2008

Dear Mr. Doyle:

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 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.

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Page 2

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 Part 801); 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.

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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Office of Compliance at one of the following numbers, based on the regulation number at the top of this letter:

21 CFR 876.xxx	(Gastroenterology/Renal/Urology)	240-276-0115
21 CFR 884.xxx	(Obstetrics/Gynecology)	240-276-0115
21 CFR 894.xxx	(Radiology)	240-276-0120
Other		240-276-0100

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 Biometrics' (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 vours.

Jorgu M. Whang

Joyce M. Whang, Ph.D. Acting Director, Division of Reproductive, Abdominal, and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):	K08919
Device Name:	NxStage PureFlow SL
Indications for Use:	The NxStage PureFlow SL module is an optional accessory tothe NxStage System One that prepares dialysate for use duringhemodialysis, as prescribed by the physician.

Prescription Use __ X (Part 21 CFR 801 Subpart D)

AND/OR

Over-The-Counter Use (21 CFR 801 Subpart C)

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

Concurrence of CDRH(Office of Device Evaluation (ODE)

(Division Sign-Off)
Division of Reproductive, Abdominal,
and Radiological Devices

510(k) Number K080919

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Special 510(k)

NxStage Page 19

Regulation Number and Section

§ 876.5820 Hemodialysis system and accessories.

(a)
Identification. A hemodialysis system and accessories is a device that is used as an artificial kidney system for the treatment of patients with renal failure or toxemic conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system and accessories to the blood compartment of the dialyzer, then returns through further tubing of the extracorporeal blood system to the patient. The dialyzer has two compartments that are separated by a semipermeable membrane. While the blood is in the blood compartment, undesirable substances in the blood pass through the semipermeable membrane into the dialysate in the dialysate compartment. The dialysate delivery system controls and monitors the dialysate circulating through the dialysate compartment of the dialyzer.(1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air foam or bubble detectors, and alarms to keep blood moving safely from the blood access device and accessories for hemodialysis (§ 876.5540) to the blood compartment of the dialyzer and back to the patient.
(2) The conventional dialyzer allows a transfer of water and solutes between the blood and the dialysate through the semipermeable membrane. The semipermeable membrane of the conventional dialyzer has a sufficiently low permeability to water that an ultrafiltration controller is not required to prevent excessive loss of water from the patient's blood. This conventional dialyzer does not include hemodialyzers with the disposable inserts (Kiil type) (§ 876.5830) or dialyzers of high permeability (§ 876.5860).
(3) The dialysate delivery system consists of mechanisms that monitor and control the temperature, conductivity, flow rate, and pressure of the dialysate and circulates dialysate through the dialysate compartment of the dialyzer. The dialysate delivery system includes the dialysate concentrate for hemodialysis (liquid or powder) and alarms to indicate abnormal dialysate conditions. This dialysate delivery system does not include the sorbent regenerated dialysate delivery system for hemodialysis (§ 876.5600), the dialysate delivery system of the peritoneal dialysis system and accessories (§ 876.5630), or the controlled dialysate delivery system of the high permeability hemodialysis system § 876.5860).
(4) Remote accessories to the hemodialysis system include the unpowered dialysis chair without a scale, the powered dialysis chair without a scale, the dialyzer holder set, dialysis tie gun and ties, and hemodialysis start/stop tray.
(b)
Classification. (1) Class II (performance standards) for hemodialysis systems and all accessories directly associated with the extracorporeal blood system and the dialysate delivery system.(2) Class I for other accessories of the hemodialysis system remote from the extracorporeal blood system and the dialysate delivery system, such as the unpowered dialysis chair, hemodialysis start/stop tray, dialyzer holder set, and dialysis tie gun and ties. The devices subject to this paragraph (b)(2) are exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 876.9.