(180 days)
The Electronic Stethoscope is intended for the detection and amplification of sounds from the heart, lungs and other internal organs with the use of a selective frequency. It can be used on any person undergoing a physical assessment for medical diagnostic purposes only.
The Mintti Electronic Stethoscope, model smartho-D2 is a healthcare device that picks up sounds of the heart, lungs and other internal organs with the use of selective frequency ranges from 10-2000Hz. After amplification and filtering, the sounds are transferred to the user's ears via an wired-connected headset.
The user interface includes a 5-button keypad and an 1.3' OLED display with a blue back-light. Sound processing is carried out with the aid of a digital signal processor.
The smartho-D2 does not incorporate any off-the-shelf (OTS) software, and it incorporates embedded software which controls all the features of the product, including sound capture, digital signal processing, volume control, OLED display and Bluetooth function.
The smartho-D2 operates on a certificated rechargeable 3.7V/2000mAh lithium ion battery.
The provided document is a 510(k) summary for the "Electronic Stethoscope - smartho-D2". It outlines the device's characteristics and its comparison to a predicate device, 3M™ Littmann® Electronic Stethoscope Model 3200 (K083903), to demonstrate substantial equivalence for regulatory clearance.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" and "reported device performance" in a separate table format. However, it provides a "Specific Comparison to Predicate" table which implicitly serves this purpose by comparing the proposed device's specifications to those of the predicate. The "Comment" column in this table indicates whether the characteristic is "Same" or "Different." For differences, the justification is that they "do not affect the basic design principle, usage, effectiveness and safety of the subject device." The performance testing section further supports these claims.
Here’s a table summarizing the implicit acceptance criteria based on the predicate comparison and the performance demonstrated by the proposed device:
| Feature/Specification | Acceptance Criteria (from Predicate) | Reported Device Performance (smartho-D2) | Status (Comment in Document) |
|---|---|---|---|
| Regulatory | |||
| Classification | Stethoscope, Electronic (Class II) | Stethoscope, Electronic (Class II) | Same |
| Regulation | 21 CFR 870.1875 | 21 CFR 870.1875 | Same |
| Product Code | DQD | DQD | Same |
| Indications for Use | Detection and amplification of sounds from heart, lungs, arteries, veins, and other internal organs for medical diagnostic purposes. | Detection and amplification of sounds from heart, lungs, and other internal organs for medical diagnostic purposes. | Different (justified as not raising different questions of safety/effectiveness) |
| Contraindications | None | None | Same |
| Power Supply Type | Battery | Battery | Same |
| Battery Type | AA alkaline, lithium, or NiMH | Rechargeable 3.7V/2000mAh lithium ion | Different (justified) |
| Battery Operation Time | 50-60 Hours | 48 Hours | Different (justified) |
| Binaural Headset | YES | YES | Same |
| Chest-piece | YES | YES | Same |
| Sound Processing | Digital signal processor | Digital signal processor | Same |
| Display Screen | LCD | 1.3' Color OLED | Different (justified) |
| Low Battery Indicator | YES | YES | Same |
| Automatic Power Off | YES | No | Different (justified) |
| Volume Control | 1-9 level | 1-4 level | Different (justified) |
| Sound Amplifier | Up to 24X | Up to 100X | Different (justified) |
| Signal Sampling Rate | 4 kHz | 8 kHz | Different (justified) |
| Frequency Response | Bell (20-1000 Hz), Diaphragm (20-2000 Hz), "Extended Range" (50-500 Hz) | 20-2000Hz (Heart Sound Mode: 20-500Hz, Lung Sound Mode: 200-2000Hz) | Different (justified) |
| Intuitive Keypad | No | NO | Same |
| A/P Chest Key | No | No | Same |
| Direct Listening | Yes (through attached binaurals) | Only via headset | Different (justified) |
| Recording and Playback | Yes (stores 12 30-sec tracks on device) | Not on the device itself | Different (justified) |
| Wireless Technology | Yes (Bluetooth 2.4 GHz) | Yes (Bluetooth 2.4 GHz) | Same |
| Ambient & Frictional Noise Reduction Technology | YES | YES | Same |
The study that "proves" the device meets these criteria is the "Performance Testing For Substantial Equivalence Evaluation" section, which includes:
- Non-Clinical Data: Biocompatibility testing, Reprocessing (Cleaning and Disinfection) validation, Electrical safety and electromagnetic compatibility (EMC) testing, Bench Testing, Software Verification and Validation Testing, Risk Analysis, and Wireless Function Testing.
- Clinical Data: None submitted.
The overall conclusion is that "The Mintti smartho-D2 Electronic Stethoscope is Substantially Equivalent (SE) to the 3M™ Littmann® Electronic Stethoscope Model 3200 cleared by K083903." This implies that the differences observed do not raise new questions of safety or effectiveness and are addressed by the performance testing.
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size for Test Set: The document does not specify a distinct "test set" sample size in terms of patient data. The non-clinical testing refers to testing on the device itself and its components. For example:
- Biocompatibility tests (Cytotoxicity, Skin Sensitization, Skin Irritation) were conducted on the "smartho-D2 Electronic Stethoscope." The sample size refers to the number of devices or components tested, not human subjects.
- Electrical safety and EMC testing were conducted on "the smartho-D2 Electronic Stethoscope device, consisting of all the modules and accessories."
- Bench testing was conducted on "the smartho-D2 Electronic Stethoscope device, consisting of all the accessories."
- The document explicitly states: "No animal or clinical testing was submitted in this 510(k)." This means there was no human or animal test set for performance on biological subjects.
- Data Provenance: Not explicitly stated for specific test data, but the submitter is Hefei Mintti Medical Technology Co., Ltd. China. Given the nature of the non-clinical testing (lab-based), the "country of origin" would likely be the location where these tests were performed, presumably China. The data would be prospective with respect to the tests conducted on the device, as they were performed to support this submission.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- As "No animal or clinical testing was submitted in this 510(k)," there was no human or animal test set requiring experts to establish ground truth in a medical diagnostic context. The ground truth for electrical safety, biocompatibility, and functional performance (e.g., frequency response, amplification) is established by adherence to recognized international standards (e.g., ISO, IEC) and internal company specifications, with the assessment of experts in those respective engineering and scientific fields (e.g., electrical engineers, biocompatibility specialists) who perform the tests and interpret the results against the standard's criteria. Their qualifications are not detailed in this summary.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Since no human or animal clinical test set with medical diagnostic outcomes was conducted, there was no adjudication method involving multiple human readers/experts comparing device output to clinical ground truth. The "adjudication" for non-clinical tests would involve comparison of test results against predefined pass/fail criteria from international standards or design specifications.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- No MRMC study was done. The device (Electronic Stethoscope - smartho-D2) is a simple electronic stethoscope for sound detection and amplification. It does not appear to incorporate AI, nor does the submission mention any AI features or claims of improving human reader performance. The device's function is to assist physicians by amplifying and filtering sounds, not to provide diagnostic interpretations or AI-assisted readings.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- The device is a hardware product (an electronic stethoscope) with embedded software for control and signal processing, not a standalone algorithm providing diagnostic output. Therefore, no standalone algorithm performance study was conducted in the sense of an AI algorithm making a diagnosis without human input. The "standalone" performance testing refers to the device's functional performance (e.g., amplification, frequency response) as a physical instrument.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- For the non-clinical performance testing:
- Biocompatibility: Ground truth is established by the pass/fail criteria specified in ISO 10993-1.
- Reprocessing: Ground truth is established by validation results demonstrating effective cleaning and disinfection, presumably against microbial reduction criteria.
- Electrical safety and EMC: Ground truth is established by compliance with IEC 60601 series standards' requirements.
- Bench Testing (functionality): Ground truth is established by design specifications (e.g., 10-2000Hz operating range, 100X amplification) that the device must meet, measured against calibrated test equipment.
- Software V&V: Ground truth is established by functional requirements and specifications that the software must fulfill, validated through testing.
- Risk Analysis: Ground truth is adherence to ISO 14971 principles and documented mitigation of identified risks.
- Wireless Function Testing: Ground truth is demonstrated by compliance with FDA Guidance on Wireless Technology, ensuring no adverse effect on safe and effective use.
- No clinical ground truth (expert consensus, pathology, or outcomes data from human/animal subjects) was used, as no clinical studies were submitted.
8. The sample size for the training set
- The document does not mention any "training set" as no machine learning or AI models are described for this device. The device is an electronic stethoscope that amplifies and filters sounds, not an algorithm that learns from data to make predictions or classifications.
9. How the ground truth for the training set was established
- Since there is no mention of a training set or machine learning, this question is not applicable to the information provided in the document.
§ 870.1875 Stethoscope.
(a)
Manual stethoscope —(1)Identification. A manual stethoscope is a mechanical device used to project the sounds associated with the heart, arteries, and veins and other internal organs.(2)
Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 870.9.(b)
Electronic stethoscope —(1)Identification. An electronic stethoscope is an electrically amplified device used to project the sounds associated with the heart, arteries, and veins and other internal organs.(2)
Classification. Class II (special controls). The device, when it is a lung sound monitor, is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 870.9.