K140571 · Nxstage Medical, Inc. · FKR · May 15, 2014 · Gastroenterology, Urology
Device Facts
Record ID
K140571
Device Name
NXSTAGE PUREFLOW SL
Applicant
Nxstage Medical, Inc.
Product Code
FKR · Gastroenterology, Urology
Decision Date
May 15, 2014
Decision
SESE
Submission Type
Special
Regulation
21 CFR 876.5820
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
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 Story
The NxStage PureFlow SL is an accessory to the NxStage System One hemodialysis system. It functions as a water proportioning and purification subsystem. It takes tap water as input, which is processed through a Pre-Treatment Unit and a Purification Pack (PAK) using deionization and ultrafiltration to meet hemodialysis water quality standards. The device then mixes the purified water with electrolyte concentrate to produce dialysate. The system includes a Control Unit (CU) for monitoring, an integrated fluid warming pad, and uses flexible LLDPE bags for dialysate storage. It is intended for use in clinical or home settings as prescribed by a physician. The system performs automated conductivity measurements on the final batch prior to treatment to ensure safety and quality. The output is dialysate, which is used by the NxStage System One to perform hemodialysis, potentially benefiting patients by enabling home-based or flexible dialysis therapy.
Clinical Evidence
Bench testing only. Performance, verification, and validation testing were conducted to characterize the device and ensure it meets predetermined acceptance criteria. No clinical data was required or provided.
Technological Characteristics
Water purification via deionization and redundant ultrafiltration. Proportioning via volumetric dosing of purified water and electrolyte concentrate. Conductivity measurement per ANSI/AAMI/ISO 26722:2009. Materials include LLDPE bags. Integrated fluid warming pad. Batch size 20-60L. Meets ANSI/AAMI/ISO 13959:2009, 11663:2009, and 13958:2009 standards.
Indications for Use
Indicated for patients requiring hemodialysis, as prescribed by a physician, using the NxStage System One.
Regulatory Classification
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.
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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: March 5, 2014 Date Name: NxStage Medical, Inc. 350 Merrimack Street Address: Lawrence, MA 01843 FDA Establishment 9045797 Owner/Operator Number: Contact Person: Mary Lou Stroumbos Director, Regulatory Affairs Phone: (978) 687-4872 Fax: (978) 687-4750 MEDIMEXICO, S. DE R.L. DE C.V. Manufacturer: Av. Valle imperial No. 10523 Parque industrial Valle Sur Tijuana, B.C., Mexico 22180
FDA Establishment Registration Number:
9616074
Sterilization Site:
Steris Isomedix, Inc. 1000 S. Sarah Place Ontario, CA 91761
Contract Sterilizer
510(k) Device Modification NxStage Medical, Inc.
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| B. Device Name: | |
|-------------------------|-------------------------------------------------------|
| Trade/Proprietary Name: | NxStage PureFlow SL |
| Common/Usual Name: | Subsystem, proportioning |
| Classification Name: | Hemodialysis systems and accessories |
| Regulation Number: | 21 CFR 876.5820 |
| Product Code: | 78 FKR |
| Device Classification: | Class II |
| Device Panel: | Gastroenterology-Urology (GU)/<br>Gastro-Renal (GRDB) |
### C. Substantial Equivalence:
P
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 predicate device as cleared through K111174 (September 19, 2011) and was found to be substantially equivalent.
### D. Device Description/Indications for Use:
The NxStage PureFlow SL module is an optional accessory to the NxStage System One used to prepare water for hemodialysis that meets ANSI/AAMI/ISO 13959:2009 and proportion it with dialysate concentrate to produce dialysate per ANSI/AAMI/ISO 11663:2009. The PureFlow SL consists of the Control Unit (CU), the water Pre-Treatment Unit, the optional OPTA Kit, the Purification Pack (PAK), and the Dialysate Sack (SAK) with Dialysate Concentrate.
510(k) Device Modification NxStage Medical, Inc.
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## Indications for use:
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.
## E. Technological Characteristics:
The proposed device has the same technological characteristics and is similar in design and configuration as compared to the predicate device.
| Table 1<br>Device Technological Characteristics Comparison Table | | |
|------------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Feature | Proposed<br>NxStage PFSL Module<br>(subject of this 510(k)) | NxStage PFSL Module<br>(K111174) |
| Indication for Use | Same | The NxStage PureFlow SL<br>module is an optional accessory<br>to the NxStage System One that<br>prepares dialysate for use during<br>hemodialysis, as prescribed by<br>the physician. |
| Water Purification | | |
| Water purification<br>technology | Same | Deionization |
| Ultrafiltration | Same | Redundant ultrafiltration replaced<br>within 12- weeks |
| Water Quality | Same | Meets or exceeds requirements<br>per ANSI/AAMI/ISO 26722:2009<br>Water treatment equipment for<br>hemodialysis applications |
| Dialysate Proportioning : | | |
| Proportioning<br>method | Same | Mixed to use Batch via<br>volumetric dosing of purified<br>water with specified amount of<br>electrolyte concentrate |
| Table 1<br>Device Technological Characteristics Comparison Table | | |
| Feature | Proposed<br>NxStage PFSL Module<br>(subject of this 510(k)) | NxStage PFSL Module<br>(K111174) |
| Conductivity<br>Measurement | Same | Yes - the System measures final<br>batch conductivity prior to each<br>treatment per ANSI/AAMI/ISO<br>26722:2009 |
| Concentrate | | |
| Dialysate<br>Concentrate | Same | Standard hemodialysis<br>concentrate per ANSI/AAMI/ISO<br>13958:2009 |
| Packaging | Same | Packaged in flexible LLDPE<br>bags with standard luer lock<br>connector. Ranging in size from<br>20L to 60L |
| Buffer | Same | Lactate |
| Point of Use Dialysate Quality | | |
| Mix-to-Use Time | Same | 96-hours |
| Bioburden | Same | AAMI/ANSI/ISO 11663:<br><100 CFU/ml |
| Endotoxin | Same | AAMI/ANSI/ISO 11663:<br><0.5 EU/ml |
| Batch size | Same | Range – 20 to 60 L<br>(40, 50 and 60L currently<br>available) |
| Fluid warming | | |
| Method | Same | Integrated fluid warming pad |
510(k) Device Modification NxStage Medical, Inc.
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# NxStage Medical, Inc.
510(k) Device Modification
NxStage Medical, Inc.
.
Confidential
.
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F. Summary of Non-Clinical Test/Performance Testing - Bench NxStage 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 device and the predetermined acceptance criteria were met. Results of this testing have documented that the proposed NxStage PureFlow SL is substantially equivalent to the predicate device and is suitable for the labeled indications for use.
510(k) Device Modification NxStage Medical, Inc.
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Image /page/5/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a stylized eagle with three tail feathers, representing the department's mission to protect the health of all Americans and provide essential human services. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular fashion around the eagle.
#### Public Health Service
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring MD 20993-0002
May 15, 2014
NxStage Medical, Inc. Mary Lou Stroumbos Director, Regulatory Affairs 350 Merrimack Street Lawrence, MA 01843
Re: K140571
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: April 17, 2014 Received: April 18, 2014
Dear Mary Lou Stroumbos,
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRFI does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies.
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Page 2 - Mary Lou Stroumbos
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); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please go to hup://www.fda.gov/AboutFDA/CentersOffices/CDRH/CDRHOffices/ucm115809.htm for the Center for Devices and Radiological Health's (CDRH's) Office of Compliance. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR 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/McdicalDevices/Safety/ReportalProblem/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/MedicalDevices/Resourcesfor You/Industry/default.htm.
Sincerely yours,
Herbert P. Lerner -S
for Beniamin R. Fisher, Ph.D. Director Division of Reproductive, Gastro-Renal, and Urological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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#### INDICATIONS FOR USE
510(k) Number (if known): K140571
NxStage® PureFlow™ SL Device Name:
The NxStage PureFlow SL module is an optional Indications for Use: accessory to the NxStage System One™ that prepares dialysate for use during hemodialysis, as
prescribed by the physician.
Prescription Use Use (Part 21 CFR 801 Subpart D) Over-The-Counter
(21 CFR 807 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
AND/OR
Concurrence of CDRH, Office of Device Evaluation (ODE)
Herbert P. Lerner-S
2014.05.15 15:31:51 -04'00'
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Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.