K182190 · Shenzhen AOJ Medical Technology Co., Ltd. · KNG · Dec 19, 2018 · Obstetrics/Gynecology
Device Facts
Record ID
K182190
Device Name
Fetal Doppler
Applicant
Shenzhen AOJ Medical Technology Co., Ltd.
Product Code
KNG · Obstetrics/Gynecology
Decision Date
Dec 19, 2018
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 884.2660
Device Class
Class 2
Indications for Use
The Fetal Doppler is intended to detect fetal heart beats, display fetal heart rate and play the fetal heart sound from early gestation thru delivery for singleton pregnancies. The Fetal Doppler is intended for use by trained healthcare professionals only in a clinical setting.
Device Story
Hand-held fetal doppler; non-invasive measurement of fetal heart rate (FHR). Input: continuous-wave ultrasound (2 MHz) reflected from fetal heart; transducer probe with two angled semi-circle crystals (one transmit, one receive). Processing: Doppler shift detection; signal conversion to FHR and audio output. Output: digital FHR display (LCD) and audible heart sounds. Used in clinical settings by trained healthcare professionals. Benefits: enables monitoring of fetal well-being during pregnancy and labor.
Clinical Evidence
Bench testing only. No clinical data provided. Testing included biocompatibility (ISO 10993-5, -10), electrical safety (IEC 60601-1), EMC (IEC 60601-1-2), and acoustic output (IEC 60601-2-37, NEMA UD2).
Technological Characteristics
Hand-held ultrasonic monitor; 2 MHz continuous-wave Doppler; wired probe with two piezoelectric crystals. Powered by 2x 1.5V AA alkaline batteries. Digital LCD display. Biocompatibility per ISO 10993. Acoustic output: Ispta < 100 mW/cm², Isata < 20 mW/cm². Software level of concern: moderate.
Indications for Use
Indicated for detection of fetal heart beats, display of fetal heart rate, and audio playback of fetal heart sounds in singleton pregnancies from 12 weeks gestation through delivery. Intended for use by trained healthcare professionals in clinical settings.
Regulatory Classification
Identification
A fetal ultrasonic monitor is a device designed to transmit and receive ultrasonic energy into and from the pregnant woman, usually by means of continuous wave (doppler) echoscopy. The device is used to represent some physiological condition or characteristic in a measured value over a period of time (e.g., perinatal monitoring during labor) or in an immediately perceptible form (e.g., use of the ultrasonic stethoscope). This generic type of device may include the following accessories: signal analysis and display equipment, electronic interfaces for other equipment, patient and equipment supports, and component parts. This generic type of device does not include devices used to image some relatively unchanging physiological structure or interpret a physiological condition, but does include devices which may be set to alarm automatically at a predetermined threshold value.
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### December 19, 2018
Shenzhen AOJ Medical Technology Co., Ltd. Qihuan Zhao General Manager Room 202, HaoGu Industry Park, 2037 Guanguang Road, Guangming district Shenzhen, 518105 China
Re: K182190
Trade/Device Name: Fetal Doppler (Models AOJ-50A and AOJ-50B) Regulation Number: 21 CFR§ 884.2660 Regulation Name: Fetal Ultrasonic Monitor and Accessories Regulatory Class: II Product Code: KNG Dated: November 8, 2018 Received: November 19, 2018
Dear Qihuan Zhao:
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 mav, 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 avare that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located 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.
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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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 of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see
https://www.fda.gov/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.html; 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 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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/MedicalDevices/Safety/ReportaProblem/default.htm.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). 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 (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
# Sharon M. Andrews -S
for
Benjamin 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) K182190
Device Name
Fetal Doppler (Models AOJ-50A and AOJ-50B)
Indications for Use (Describe)
The Fetal Doppler is intended to detect fetal heart beats, display fetal heart rate and play the fetal heart sound from early gestation thru delivery for singleton pregnancies. The Fetal Doppler is intended for use by trained healthcare professionals only in a clinical setting.
Type of Use (Select one or both, as applicable)
| <span></span> | Prescription Use (Part 21 CFR 801 Subpart D) |
|---------------|----------------------------------------------|
| <span></span> | Over-The-Counter Use (21 CFR 801 Subpart C) |
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## 510(k) Summary - K182190
#### 1. Submitter
| Name and Address | Shenzhen AOJ Medical Technology Co., Ltd.<br>Room 202, HaoGu industry park, 2037 Guanguang road, Guangming district,<br>518105, Shenzhen, P.R. China<br>Tel.: +86 18603031299 |
|------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Contact Person: | Qihuan Zhao, General Manager, Shenzhen AOJ Medical Technology Co., Ltd. |
| Date Prepared: | December 17, 2018 |
#### 2. Device Information
| Trade Name: | Fetal Doppler (Models AOJ-50A, AOJ-50B |
|------------------------|------------------------------------------|
| Common Name: | Fetal doppler |
| Classification Name: | Fetal ultrasonic monitor and accessories |
| Regulation Number: | 21 CFR 884.2660 |
| Device Classification: | Class II |
| Product Code: | KNG (monitor, ultrasonic, fetal) |
| Review Panel: | Obstetrics/Gynecology |
#### 3. Predicate Device
| 510(k) Number: | K180419 |
|----------------|--------------------------------------------|
| Device Name: | YM-2T8 Ultrasonic Doppler |
| Manufacturer: | Shenzhen IMDK Medical Technology Co., Ltd. |
The predicate device has not been subject to a design-related recall.
#### 4. Device Description
The Fetal Doppler is a hand-held device for non-invasive measurement and display of the fetal heart beat utilizing the principle of Doppler shift of an ultrasound. The device consists of two main components, the main unit and probe. The main unit consists of the main board, power module, battery, speaker, and organic light-emitting diode screen. The wired probe consists of the transducer and includes two angled semi-circle ultrasonic crystals, one for transmission and one for reception. The ultrasonic signal is continuously transmitted at a frequency of 2 MHz. The reflected continuous wave signal is received by one of the crystals and then any detected Doppler shift is presented to the user.
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The main unit is powered by two 1.5V AA alkaline batteries. The use-life of the device is five years.
#### 5. Indications for Use
The Fetal Doppler is intended to detect fetal heart beats, display fetal heart rate and play the fetal heart sound from early gestation thru delivery for singleton pregnancies. The Fetal Doppler is intended for use by trained healthcare professionals only in a clinical setting.
#### 6. Predicate Comparison
The following table compares the Fetal Doppler to the predicate device with respect to the indications for use and technological characteristics:
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| Comparison Items | Predicate Device | Subject Device | Comparison<br>Result |
|-----------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------|
| | Ultrasonic Doppler | Fetal Doppler | |
| | Model: YM-2T8 | | |
| 510(k) Number | K180419 | K182190 | ---- |
| Manufacturer | Shenzhen IMDK Medical<br>Technology Co., Ltd. | Shenzhen AOJ Medical Technology Co.,<br>Ltd. | ---- |
| Classification Name | Fetal ultrasonic monitor and<br>accessories | Fetal ultrasonic monitor and accessories | Same |
| Regulation Number | 844.2660 | 844.2660 | Same |
| Device Class | Class II | Class II | Same |
| Product Code | KNG | KNG | Same |
| Indications for Use | The Ultrasonic Doppler uses<br>continuous-wave Doppler to<br>detect fetal heart beats, display<br>fetal heart rate and play the fetal<br>heart sound from early gestation<br>thru delivery for singleton<br>pregnancies. The Ultrasonic<br>Doppler is intended for use by<br>trained healthcare professionals<br>only in a clinical setting. | The Ultrasonic Doppler is intended to<br>detect fetal heart beats, display fetal heart<br>rate and play the fetal heart sound from<br>early gestation thru delivery for singleton<br>pregnancies. The Ultrasonic Doppler is<br>intended for use by trained healthcare<br>professionals only in a clinical setting. | Same |
| Gestational Age | 12 weeks | 12 weeks | Same |
| Gestational Type | Singleton | Singleton | Same |
| Technical Characteristics | | | Same |
| Display Type | Digital Display; LCD | Digital Display; LCD | Same |
| Power Suppler | 2* 1.5V AA Alkaline batteries | 2* 1.5V AA Alkaline batteries | Same |
| Probe connection | Wired | Wired | Same |
| Acoustic Output<br>Power | 3 W | 3 W | Same |
| Nominal Frequency | 2 MHz | 2 MHz | Same |
| Working Frequency | (2.0 ± 10%) MHz | (2.0 ± 10%) MHz | Same |
| $I_{ob}$ | < 20 $mW/cm^2$ | < 20 $mW/cm^2$ | Same |
| $p_r$ | 1 MPa | 1 MPa | Same |
| $I_{spta}$ | < 100 $mW/cm^2$ | < 100 $mW/cm^2$ | Same |
| $I_{sata}$ | < 20 $mW/cm^2$ | < 20 $mW/cm^2$ | Same |
| $W_o$ | 50 mW | 50 mW | Same |
| Mode of operation | Continuous Wave Doppler | Continuous Wave Doppler | Same |
| Effective Radiating<br>Area | (157±30%) mm² | (157±30%) mm² | Same |
| FHR Measuring<br>Range | 50 bpm -210 bpm | 50 bpm - 210 bpm | Same |
| Accuracy | ± 2bpm | ± 2bpm | Same |
| Resolution | 1 bpm | 1 bpm | Same |
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As evidenced by the table above, the subject and predicate device have similar technological characteristics. The differences in technological characteristics between the subject and predicate device do not raise different questions of safety or effectiveness.
#### 7. Non-Clinical Performance Testing
The following performance data were provided in support of the substantial equivalence determination:
### Biocompatibility
The biocompatibility evaluation was conducted in accordance with ISO 10993-1, Biological Evaluation of Medical Devices - Part 1: Evaluation and Testing Within a Risk Management Process. Patient contacting materials were subjected to testing that included the following tests:
- Cytotoxicity (ISO 10993-5)
- Skin Sensitization (ISO 10993-10)
- Irritation (ISO 10993-10)
### Electrical safety and electromagnetic compatibility (EMC)
Electrical safety and EMC testing were conducted and the device was found to comply with the requirements of the following standards:
- IEC 60601-1, Medical Electrical Equipment - Part 1: General requirements for basic safety and essential performance with US deviations per AAMI/ANSI ES 60601-1
- IEC 60601-1-2, Medical Electrical Equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances- requirements and tests
### Ultrasound and Acoustic Testing
Bench testing was conducted on the Fetal Doppler and the system was found to comply with the following:
- IEC 60601-2-37 Medical electrical equipment - Part 2-37: Particular requirements for the basic safety and essential performance of ultrasonic medical diagnostic and monitoring equipment
- Acoustic Output testing per NEMA UD2, Acoustic Output Measurement Standard for Diagnostic Ultrasound Equipment
The acoustic output measurement methodology as recommended in FDA guidance document "Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers," dated September 9, 2008 was followed for Track 1 devices.
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### Software Verification and Validation Testing
Software verification and validation testing was conducted with no outstanding anomalies. Software documentation was provided as recommended by FDA guidance document "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices," dated May 11, 2005 for a moderate software level of concern.
#### Conclusion 8.
Based on the comparison and analysis above, the Fetal Doppler is substantially equivalent to the predicate device.
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.