K251851 · Fresenius Medical Care Renal Therapies Group, LLC · FIP · Oct 9, 2025 · Gastroenterology, Urology
Device Facts
Record ID
K251851
Device Name
DIASAFEplusUS (F00013010)
Applicant
Fresenius Medical Care Renal Therapies Group, LLC
Product Code
FIP · Gastroenterology, Urology
Decision Date
Oct 9, 2025
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 876.5665
Device Class
Class 2
Indications for Use
The DIASAFE®plusUS is intended for the preparation of ultrapure dialysis fluid (for the 2008-series machines and 5008X machines) and sterile, non-pyrogenic substitution fluid (for the 5008X machines) from pretreated water and is not intended to provide primary purification. Attention must still be given to the chemical and microbiological quality of water and concentrates and the maintenance of supply systems (e.g. RO system, central delivery system). The microbiological quality (microbial count [CFU/mL] and endotoxin measurement [EU/mL]) of the incoming water should be < 200 CFU/mL and < 2 EU/mL, respectively. The DIASAFE®plusUS can only be used with Fresenius Medical Care hemodialysis machines fitted for use with the DIASAFE®plusUS.
Device Story
DIASAFEplusUS is a non-sterile fluid filter for hemodialysis machines; produces ultrapure dialysis fluid and sterile, non-pyrogenic substitution fluid. Input: pretreated water/dialysis fluid. Operation: fluid forced through polysulfone-polyvinylpyrrolidone capillary fibers; microorganisms/large molecules trapped in fibers; flushed/disinfected during routine machine cycles. 2008-series machines use one filter; 5008X machines use two filters (one for dialysis fluid, second for substitution fluid). Used in acute/chronic hemodialysis/hemodiafiltration environments. Installed via DIAFIX Lock System. Output: filtered fluid for hemodialyzer or infusion. Benefits: reduces microbial contaminants/endotoxins in dialysate; enables on-line HDF treatments.
Clinical Evidence
No clinical studies were performed. Device is identical to the predicate in design and materials; bench testing and biocompatibility data from the predicate apply.
Technological Characteristics
Filter housing: polypropylene; capillary fibers: polysulfone-polyvinylpyrrolidone blend; potting mass: polyurethane; O-rings/seals: silicone. Filtration rate: ≥ 300 mL/hr/mmHg. Surface area: 2.1 m². Max pressure: 2 bar. Max life: 90 days. Non-electrical, mechanical filtration.
Indications for Use
Indicated for preparation of ultrapure dialysis fluid and sterile, non-pyrogenic substitution fluid for use in chronic and acute hemodialysis and hemodiafiltration. Compatible with Fresenius 2008-series and 5008X machines. Requires incoming water quality < 200 CFU/mL and < 2 EU/mL.
Regulatory Classification
Identification
A water purification system for hemodialysis is a device that is intended for use with a hemodialysis system and that is intended to remove organic and inorganic substances and microbial contaminants from water used to dilute dialysate concentrate to form dialysate. This generic type of device may include a water softener, sediment filter, carbon filter, and water distillation system.
Special Controls
*Classification.* Class II (special controls). The device, when it is a water purification subsystem disinfectant, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 876.9.
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FDA U.S. FOOD & DRUG ADMINISTRATION
October 9, 2025
Fresenius Medical Care Renal Therapies Group, LLC
Timothy Groves
Regulatory Affairs - Senior Lead
920 Winter Street
Waltham, MA 02451
Re: K251851
Trade/Device Name: DIASAFEplusUS (F00013010)
Regulation Number: 21 CFR§ 876.5665
Regulation Name: Water Purification System For Hemodialysis
Regulatory Class: II
Product Code: FIP
Dated: June 16, 2025
Received: September 16, 2025
Dear Timothy Groves:
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 (the 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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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: CDRH 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.
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
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K251851 - Timothy Groves
Page 2
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
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); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
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K251851 - Timothy Groves
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For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Maura Rooney -S
Maura Rooney
Assistant Director
DHT3A: Division of Renal, Gastrointestinal, Obesity and Transplant Devices
OHT3: Office of GastroRenal, ObGyn, General Hospital and Urology Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Enclosure
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DIASAFEplusUS
Page 8 of 36
| Indications for Use | | |
| --- | --- | --- |
| Please type in the marketing application/submission number, if it is known. This
textbox will be left blank for original applications/submissions. | K251851 | ? |
| Please provide the device trade name(s). | | ? |
| DIASAFEplusUS (F00013010) | | |
| Please provide your Indications for Use below. | | ? |
| The DIASAFE®plusUS is intended for the preparation of ultrapure dialysis fluid (for the 2008-series
machines and 5008X machines) and sterile, non-pyrogenic substitution fluid (for the 5008X machines) from
pretreated water and is not intended to provide primary purification. Attention must still be given to the
chemical and microbiological quality of water and concentrates and the maintenance of supply systems
(e.g. RO system, central delivery system). The microbiological quality (microbial count [CFU/mL] and
endotoxin measurement [EU/mL]) of the incoming water should be < 200 CFU/mL and < 2 EU/mL,
respectively. The DIASAFE®plusUS can only be used with Fresenius Medical Care hemodialysis machines
fitted for use with the DIASAFE®plusUS. | | |
| Please select the types of uses (select one or both, as
applicable). | ☑ Prescription Use (Part 21 CFR 801 Subpart D)
☐ Over-The-Counter Use (21 CFR 801 Subpart C) | |
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FRESENIUS MEDICAL CARE
510(k) Summary DIASAFE®plusus Traditional 510(k)
K251851 Page 1 of 4
# 1. 510(K) SUMMARY
This 510(k) Summary is in accordance with the requirements of the Safe Medical Device Act (SMDA) of 1990. The content of this 510(k) summary is provided in conformance with 21 CFR § 807.92.
## 1.1. Submitter's Information
Name: Fresenius Medical Care Renal Therapies Group, LLC
Address: 920 Winter Street
Waltham, MA 02451-1457
Phone: (781) 460-1087
Fax: (781) 699-9635
Contact Person: Timothy Groves, Senior Lead
Preparation Date: 16 June 2025
## 1.2. Device Name
Trade Name: DIASAFEplusUS (F00013010)
Common Name: Fluid filter
Regulation Name: Water purification system for hemodialysis
Regulatory Class: Class II per 21 CFR § 876.5665
Product Code: FIP
Product Code Name: Subsystem, water purification
FDA Review Panel: Gastroenterology/Urology
## 1.3. Legally Marketed Predicate Device
The legally marketed primary predicate device is the DIASAFE®plusUS filter cleared under K243505. The predicate has not been subject to a design-related recall.
## 1.4. Device Description
### 1.4.1. Device Identification
The DIASAFE®plusUS (F00013010) is the subject of this Traditional 510(k).
### 1.4.2. Device Characteristics
The DIASAFE®plusUS is a non-sterile dialysis fluid filter that produces ultrapure dialysis fluid (for the 2008-series machines and 5008X machines) and sterile, non-pyrogenic substitution fluid (for the 5008X machines) for use in chronic and acute hemodialysis and hemodiafiltration. The DIASAFE®plusUS reduces microbial contaminants including endotoxin in the dialysate during treatments. The DIASAFE®plusUS is available in one (1) configuration and is compatible for use with 2008 series and 5008X hemodialysis machines. It is installed on the hemodialysis machines
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#
FRESENIUS MEDICAL CARE
510(k) Summary DIASAFE®plusus Traditional 510(k)
K251851 Page 2 of 4
using the DIAFIX™ Lock System. The DIAFIX™ Lock System is a standard feature on the hemodialysis machines and is installed during machine production.
# 1.4.3. Environment of Use
The DIASAFE®plusus is used in environments where acute and chronic hemodialysis and hemodiafiltration are performed.
# 1.4.4. Brief Written Description of the Device
The 2008 series hemodialysis machines use 1 DIASAFE®plusus. Mixed dialysis fluid is forced through an open filter port across the fibers of the DIASAFE®plusus. A closed bypass valve at the other end forces the dialysis fluid across the fiber membrane. Dialysis fluid passes through the porous membrane and into the filtrate compartment where it is allowed to flow through the uncapped side ports and into the hemodialyzer. Microorganisms and molecules too large to pass through the membrane are trapped in the fibers until they are flushed out, and/or disinfected during a routine cleaning cycle.
The 5008X hemodialysis system uses two (2) DIASAFE®plusus for preparation of the dialysis and substitution fluid which can be used for up to 100 on-line HDF treatments. The dialysis fluid is filtered by the first DIASAFE®plusus. A second DIASAFE®plusus is used to filter the ultrafiltered dialysis fluid a second time to prepare the substitution fluid. The substitution fluid can be infused in the post-dilution mode (i.e., after the blood has passed through the dialyzer), in the pre-dilution mode (i.e., before the blood enters the dialyzer), or combined.
# 1.4.5. Materials of Use
The DIASAFE®plusus is classified as an externally communicating, blood path indirect, long-term contact (> 30 days, Category C) duration, Class II device in accordance with FDA guidance Use of International Standard ISO 10993-1, Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk management process (08 September 2023).
The DIASAFE®plusus components are composed of the materials listed in Table 1.
Table 1: DIASAFE®plusus Component Materials
| Component | Material |
| --- | --- |
| Capillary Fibers (fiber bundle) | Polysulfone-polyvinylpyrrolidone blend |
| Filter Housing | Polypropylene |
| PU-Resin (potting mass) | Polyurethane |
| O-ring | Silicone |
| Welded Header (cap/flange) | Polypropylene |
| Plastic Tabs (tear-off brackets) | Silicone |
| Sealing Disc-ring | Silicone |
# 1.4.6. Key Performance Specifications/Characteristics
Performance specifications for the DIASAFE®plusus are provided in Table 2.
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FRESENIUS MEDICAL CARE
510(k) Summary
DIASAFE®plusUS Traditional 510(k)
K251851
Page 3 of 4
Table 2: DIASAFE®plusUS Features
| Features | Specifications |
| --- | --- |
| Filtration Rate | ≥ 300 mL/hr/mmHg
≥ 3.75 L/min/bar |
| Maximum Filtration Pressure | 2 bar |
| Surface Area | 2.1 m² |
| Connection System | DIAFIX™ Lock System |
| Dialysis Fluid Purity | Ultrapure dialysis fluid:
< 0.03 EU/mL
< 0.1 CFU/mL
Supports generation of sterile, non-pyrogenic substitution fluid |
| Maximum Use Life | 90 days |
## 1.5. Intended Use
Purification of dialysis fluid (for the 2008-series machines and 5008X machines) and online hemodiafiltration (HDF) fluid (for the 5008X machines).
## 1.6. Indications for Use
The DIASAFE®plusUS is intended for the preparation of ultrapure dialysis fluid (for the 2008-series machines and 5008X machines) and sterile, non-pyrogenic substitution fluid (for the 5008X machines) from pretreated water and is not intended to provide primary purification. Attention must still be given to the chemical and microbiological quality of water and concentrates and the maintenance of supply systems (e.g. RO system, central delivery system).
The microbiological quality (microbial count [CFU/mL] and endotoxin measurement [EU/mL]) of the incoming water should be < 200 CFU/mL and < 2 EU/mL, respectively.
The DIASAFE®plusUS can only be used with Fresenius Medical Care hemodialysis machines fitted for use with the DIASAFE®plusUS.
## 1.7. Comparison of Technological Characteristics with the Predicate Device
The proposed DIASAFE®plusUS has the same principle of operation, materials, design specifications, and performance requirements as the predicate device (K243505). There are no changes to the DIASAFE®plusUS that impact performance. The changes being proposed are limited to labeling.
## 1.8. Performance Data
The proposed DIASAFE®plusUS is identical to the predicate DIASAFE®plusUS with respect to manufacturing, design, and materials. The proposed labeling changes do not impact the performance of the dialyzers.
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FRESENIUS MEDICAL CARE
510(k) Summary DIASAFE®plus™ Traditional 510(k)
K251851 Page 4 of 4
## 1.8.1. Biocompatibility Testing
The proposed DIASAFE®plus™ is identical to the predicate DIASAFE®plus™ with respect to manufacturing, design, and materials. The proposed labeling changes do not impact the biological safety of the dialyzers.
## 1.8.2. Human Factors Validation Testing
The DIASAFE®plus™ was found to be safe and effective for its intended users, uses, and use environments.
## 1.8.3. Electrical Safety and Electromagnetic Compatibility (EMC)
Not applicable. The DIASAFE®plus™ is not an electrical mechanical device.
## 1.8.4. Software Verification and Validation Testing
Not applicable. The DIASAFE®plus™ does not contain software.
## 1.8.5. Animal Studies
No animal studies were performed.
## 1.8.6. Clinical Studies
No clinical studies were performed.
## 1.9. Conclusion
The intended use, indications for use, principle of operation, technological characteristics, design, materials, and performance requirements are substantially equivalent to those of the predicate device. FMCRTG concludes that within the meaning of the Medical Device Amendments Act of 1976, the DIASAFE®plus™ is safe and effective for its intended use.
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.