The SORB+ and HISORB+ Cartridges are to be used only with Renal Solutions' REDY Sorbant Dialysis systems for the treatment of acute and chronic uremic patients where hemodialysis is prescribed by the physician.
Device Story
Sorbent dialysis system uses chemical cartridges to remove urea and waste from dialysate, allowing recirculation and regeneration of dialysate. Input: spent dialysate from dialyzer. Process: dialysate passes through multi-layer cartridge containing activated carbon (absorbs organic waste), immobilized urease (breaks down urea to ammonium carbonate), zirconium phosphate (removes ammonium, releases sodium/hydrogen), and hydrous zirconium oxide/sodium zirconium carbonate (removes phosphate, fluoride, heavy metals). Output: purified, partially regenerated dialysate, which is then reconstituted by the machine (reinfusing calcium, magnesium, potassium) and returned to the dialyzer. Used in clinical settings for hemodialysis; operated by trained personnel. Benefits: significantly reduces water consumption (6L vs 120L per session) compared to single-pass systems.
Clinical Evidence
Bench testing only. No clinical data provided. Testing included validation of toxic chemical contamination levels per AAMI/ANSI RD5-1992 and RD62-2000/2001, endotoxin and bacteria removal, biocompatibility (cytotoxicity, irritation, systemic toxicity per ISO 10993), and capacity verification against published specifications. Performance compared to predicate cartridges via in-vitro testing.
Technological Characteristics
Multi-layer cartridge containing activated carbon, immobilized urease, zirconium phosphate, hydrous zirconium oxide, and sodium zirconium carbonate. Non-sterile, single-use. Operates via ion exchange and adsorption. Dimensions/form factor not specified. Standalone component for use within REDY Sorbent Hemodialysis System. Biocompatibility per ISO 10993.
Indications for Use
Indicated for acute and chronic uremic patients requiring hemodialysis treatment.
Regulatory Classification
Identification
A sorbent regenerated dialysate delivery system for hemodialysis is a device that is part of an artificial kidney system for the treatment of patients with renal failure or toxemic conditions, and that consists of a sorbent cartridge and the means to circulate dialysate through this cartridge and the dialysate compartment of the dialyzer. The device is used with the extracorporeal blood system and the dialyzer of the hemodialysis system and accessories (§ 876.5820). The device includes the means to maintain the temperature, conductivity, electrolyte balance, flow rate and pressure of the dialysate, and alarms to indicate abnormal dialysate conditions. The sorbent cartridge may include absorbent, ion exchange and catalytic materials.
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Page 1 of 6
# SEP 1 7 2003
Renal Solutions
## Appendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges
510(k) K031099
March 31, 2003 Date of Application Renal Solutions Inc, Sorb Technology Division Submitters 3631 SW 54th Street Name Oklahoma City, OK 73119 USA Phone 405-682-1993 FAX- 405-682-2108 Richard G. Confer, V.P. RA and QA Contact Name Renal Solutions 770 Commonwealth Drive, Suite 101 Warrendale, PA 15086 e-mail: rick.confer@renalsolutionsinc.com Trade Name SORB+ and HISORB+ System, Dialysate Delivery, Sorbent Regenerated, Accessory Common Name Classification Class II per 21CFR876.5600 code FKT K811170- SORB 3160- manufactured by Sorb Technology Predicate Device K812869-HISORB 3260- manufactured by Sorb Technology Information
#### Summary of Safety and Effectiveness
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RenalSolutions
## Annendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges
Device Description Sorbent (or regenerative) dialysis systems use the chemical action of a sorbent cartridge to remove urea and other waste materials from the dialysate and return the fresh dialysate to the dialysate holding tank. This fresh dialysate then passes through a dialyzer, removes additional waste material, and re-circulates through the sorbent cartridge to continue the process. This contrasts to traditional "single pass" dialysis, which uses purified water passing across the dialysate side of a dializer membrane in a single flow-through system to remove urea and other waste materials from the dialysis patient's bloodstream. Wastewater is routed to a drain and not recirculated. By re-circulating and refreshing the dialysate, the Renal Solutions' REDY System uses 6L of water per dialysis treatment. A traditional single pass dialysis system uses at least 120L of purified water during the typical 4 hour dialysis session.
KO31099
The SORB+ and HISORB+ Cartridges are intended to be used in a Renal Solutions REDY Sorbent Hemodialysis System as the chemical agents that absorb the urea and other waste material from the dialysate stream. This system is represented schematically in the following diagram.
Two models of SORB Cartridges are available and have sufficient capacity to adsorb patient dialysis waste products presented to them during a usual dialysis procedure within the limits given below. It is recommended that the patient dialyzable volume, pre-dialysis BUN, dialyzer clearance, and treatment time be sufficient to provide the removal of urea-nitrogen within these limits for each model of Sorbant Cartridge:
#### SORB™ +
The SORB+ Cartridge has an approximate urea-nitrogen capacity of from 9.5 grams to 23.5 grams.
HISORB +
The HISORB+ Cartridge has an approximate urea-nitrogen capacity of from 23.5 grams to 35.0 grams. Both cartridges use the same theory of removing toxins from the dialysate. The initial dialysate is made by dissolving the REDY Chem™ dialysate and dialysate additives in six (6) liters of potable (per EPA requirements) water. The REDY Chems are non-sterile, single use, unit dose packages of various weights used individually and in combination according to the physician's prescription of sodium bicarbonate, sodium chloride, dextrose, and ascorbic acid chloramine reducing agent. The resulting dialysate is added to the machine and pumped to the
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K031099
Page 3 of 6
RenalSolutions
Appendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges dialyzer, taking up the uremic toxins from the patient's blood.
Cartridge Construction
Image /page/2/Figure/5 description: The image shows a diagram of a dialysis system with different layers. The layers include Zirconium Oxide & Zr Carbonate Layer, Zirconium Phosphate Layer, Urease Layer, and Activated Carbon & Purification Layer. The diagram also indicates what each layer binds and releases, such as the Zirconium Oxide & Zr Carbonate Layer binding Phosphate, Fluoride, and Heavy Metals, and releasing Acetate, Bicarbonate (more), and Sodium.
The dialysate, after passing through the dialyzer, passes through the SORB+ (or HISORB+) Cartridge where it is purified and partially regenerated. The SORB+ Cartridges are non-sterile products intended for single use only. They contain, in the first layer, activated carbon (AC) as an absorbent purification material and also as a filler material. The primary purpose of the bulk of the AC is to absorb organic wastes from the patient such pure absorbent with no release of counter ions or effect or dependency on the other layers.
The second layer contains immobilized urease enzyme (IU) that breaks down the patient's waste urea into ammonium carbonate. It contains a natural enzyme and purified alumina that acts to bind and immobilize the enzyme in the Sorbent Cartridge in both a combined and a separate layer.
The next layer, containing the cation exchange material zirconium
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K031099
Image /page/3/Picture/1 description: The image contains a logo for Renal Solutions. The logo consists of a stylized graphic on the left and the text "Renal Solutions" on the right. The graphic appears to be an abstract representation of interconnected shapes. The text "Renal Solutions" is in a bold, sans-serif font, with "Renal" being larger and darker than "Solutions."
## Appendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges
phosphate (ZP) removes the ammonium ion from the IU layer and donates sodium and hydrogen ions in a controlled release, which combine with the remaining carbonate ion to make sodium bicarbonate in proper balance for regenerative dialysis. The ZP also removes other cations from the dialysate such as calcium, magnesium, and potassium, which are essential components of the dialysate.
The final layer in the Sorbent Cartridge contains the anion exchange material hydrous zirconium oxide in the acetate counter ion form (HZO) and sodium zirconium carbonate (SZC). These materials remove the waste metabolite phosphate ions and other highly charged anionic metals from both the initial water source and from the patient, such as fluoride and aluminum.
After the purified and partially regenerated dialysate leaves the Sorbent Cartridge, it is fully reconstituted by the machine by reinfusing the calcium, magnesium, and potassium removed by the Sorbent Cartridge. The fully purified and reconstituted dialysate is then continually pumped back to the dialyzer where the cycle starts again.
The clinical result is dependent upon both the cartridge selection and performance, and the dialysate chemical selection and performance working together. That is, it is also dependent in conjunction with rest of the Dialysis Prescription for the specific patient, his/her condition, the dialyzer selection and performance, the dialysate flow rate, the blood flow rate, the ultrafiltration amount and rate, the length of time of dialysis, and the frequency of dialysis.
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KO31099
Page 5 of 6
Image /page/4/Picture/2 description: The image shows the logo for Renal Solutions. The logo consists of a stylized graphic to the left of the text "Renal Solutions". The graphic appears to be a stylized representation of two interconnected shapes, possibly representing kidneys or a similar concept related to renal health. The text "Renal Solutions" is in a bold, sans-serif font, with "Renal" being larger than "Solutions".
## Appendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges
The SORB+ and HISORB+ Cartridges are to be used only with Intended Use Renal Solutions' REDY Sorbant Dialysis systems for the treatment of acute and chronic uremic patients where hemodialysis is prescribed by the physician.
The SORB+ and HISORB+ Cartridges have been tested for Summary of conformance to their design specifications for materials and Testing construction, and chemical performance in simulated patient use The cartridges also have been tested for their conditions. effectiveness in purifying water or dialysate to safe levels for dialysis, biocompatibility, and endotoxin and bacteria removal.
The results of the testing are as follows:
| Testing Topic | Reference Standards | Results |
|---------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------|---------|
| Validation of Maximum<br>Allowable Contamination<br>Levels of Toxic<br>Chemicals in Water<br>Supply for the SORB+<br>and HISORB+ Cartridges | AAMI/ANSI, RD5-<br>1992 and RD62-2000,<br>RD62, 2001 | Pass |
| Limit Test of Endotoxin<br>and Bacteria Removal by<br>SORB+ and HISORB+<br>Cartridges | AAMI/ANSI | Pass |
| Biocompatibility<br>Validation of SORB + and<br>HISORB + Cartridges | ISO 10993<br>cytotoxicity, irritation<br>or intracutaneous<br>reactivity, and systemic<br>toxicity (acute). | Pass |
| Validation Testing of<br>SORB+ and HISORB+<br>Cartridges | Sorb Technologies<br>published capacity<br>specifications | Pass |
In addition, the performance of the SORB+ and HISORB+ Cartridges was compared to the performance of the current version of the SORB and HISORB Cartridges in in-vitro testing.
The acceptability of the current SORB and HISORB Cartridges for
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K031099 Page 6 of 6
Image /page/5/Picture/1 description: The image shows the logo for Renal Solutions. The logo consists of a circular graphic on the left and the words "Renal Solutions" on the right. The word "Renal" is in bold, while the word "Solutions" is in a lighter, non-bold font.
## Appendix 1-B Summary of Safety and Effectiveness 510(k) Summary SORB+ and HISORB+ Cartridges
use in sorbent dialysis systems has been established in clinical testing and during clinical use since their clearance for market. (Refer to K81170 and K812869).
Conclusions
performed on the SORB+ and HISORB+ Cartridges All testing verifies the substantial equivalency of these cartridges to the predicate, SORB and HISORB Cartridges, when used with the Renal Solutions Sorbent Dialysis system for acute and chronic hemodialysis.
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Image /page/6/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS) of the United States. The seal features the department's name, "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA," arranged in a circular pattern around a central emblem. The emblem consists of a stylized caduceus-like symbol, with three parallel lines representing the branches of the department, and a human profile in the negative space between the lines.
Public Health Service
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
SEP 1 7 2003
Mr. Richard Confer Senior V.P. Compliance and Regulatory Affairs Renal Solutions™, Inc. 770 Commonwealth Drive, Suite 101 WARRENDALE PA 15086
Re: K031099
Trade/Device Name: SORB+ and HISORB+ Cartridges Regulation Number: 21 CFR §876.5600 Regulation Name: Sorbent regenerated dialysate delivery system for hemodialysis Regulatory Class: II Product Code: 78 FKT Dated: August 12, 2003 Received: August 13, 2003
Dear Mr. Confer:
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. Iisting 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 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. 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.
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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 the letter:
| 8xx.1xxx | (301) 594-4591 |
|----------------------------------|----------------|
| 876.2xxx, 3xxx, 4xxx, 5xxx | (301) 594-4616 |
| 884.2xxx, 3xxx, 4xxx, 5xxx, 6xxx | (301) 594-4616 |
| 892.2xxx, 3xxx, 4xxx, 5xxx | (301) 594-4654 |
| Other | (301) 594-4692 |
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" (21CFR Part 807.97) you may obtain. Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.
Sincerely yours,
Nancy C. Brogdon
Nancy C. İ rogdon Director, Division of Reproductive, Abdominal and Radiological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
Page 2
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K031099
Appendix 1-A
Ver/ 3 - 4/24/96 Applicant: Renal Solutions, Inc.
Applicant Name: Christine Hill
510(k) Number (if known): K031099
### Device Name: SORB+ and HISORB+ Cartridges
Indications For Use:
The SORB+ and HISORB+ Cartridges are to be used only with Renal Solutions' REDY Sorbant Dialysis systems for the treatment of acute and chronic patients where hemodialysis is prescribed by the physician.
(PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE) (Per 21 CFR 801.109)
Division 'sign Off
| 510(k) Number | ____________________ |
|---------------|----------------------|
|---------------|----------------------|
Prescription use V or Over-the-counter ____________________P (Per 21 CFR 801.109)
Over-the-counter
(Optional Format 1-2-96)
David A. Lyon
(Division Sign-Off) Division of Reproductive Abdominal, and Radiological Det 510(k) Number
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.