Drugdu.com expert's response:

The U.S. Food and Drug Administration (FDA) classifies medical devices into three categories—Class I (low-risk), Class II (medium-risk), and Class III (high-risk)—based on their risk levels, and implements differentiated regulatory requirements for each category. Below is a detailed explanation of the classification logic and regulatory framework:

I. Classification Basis: Risk Level and Regulatory Control

The FDA's classification system is grounded in the Federal Food, Drug, and Cosmetic Act (FD&C Act) and the Medical Device Amendments (MDA), with the core principle that higher risk warrants stricter regulation. Specific classification criteria are as follows:

Class I (Low-Risk)

Risk Characteristics: Non-invasive, non-life-supporting, with minimal potential harm to the human body.

Regulatory Requirements:

Implementation of General Controls, including prohibiting the sale of non-compliant products, reporting adverse events, and restricting sales scope.

Approximately 93% of Class I devices are exempt from 510(k) submissions, requiring only Enterprise Registration and Product Listing.

A minority of Class I devices (e.g., medical gloves, surgical blades) must submit a 510(k) application to demonstrate "substantial equivalence" to predicate devices.

Typical Products: Thermometers, tongue depressors, manual surgical instruments, medical dressings, crutches, etc.

Proportion: Accounting for approximately 27% of all medical devices.

Class II (Medium-Risk)

Risk Characteristics: May pose certain risks to the human body, but risks can be mitigated through special controls.

Regulatory Requirements:

Implementation of General Controls + Special Controls, including performance standards, labeling requirements, and post-market surveillance.

Requires submission of a 510(k) Premarket Notification to demonstrate substantial equivalence to predicate devices in intended use, technical characteristics, and performance testing.

Review period typically exceeds six months, with no mandatory on-site quality system inspections (unless randomly selected by the FDA).

Typical Products: Electronic blood pressure monitors, ultrasound diagnostic systems, infusion pumps, ventilators, extracorporeal circulation devices, dental implants, etc.

Proportion: Accounting for approximately 46% of all medical devices.

Class III (High-Risk)

Risk Characteristics: Directly support or sustain life, or are implanted in the human body, with significant potential harm.

Regulatory Requirements:

Implementation of General Controls + Premarket Approval (PMA), requiring scientific evidence to demonstrate safety and effectiveness.

Review period typically exceeds one year, with mandatory on-site quality system inspections (QSR820) by the FDA prior to approval.

Requires continuous submission of clinical data and algorithm iteration information (e.g., for AI-enabled medical devices).

Typical Products: Artificial heart valves, cardiac pacemakers, implantable defibrillators, artificial joints, neurostimulators, etc.

Proportion: Accounting for approximately 7% of all medical devices.

II. Special Classifications and Dynamic Adjustments

AI/ML Medical Device Classification Rules (2025 Edition)

The FDA classifies AI-enabled medical devices into Classes I–III based on algorithm interpretability, data transparency, and clinical decision-making impact.

Class III AI products (e.g., dynamic learning diagnostic software) require PMA applications, with registration costs 40% higher than traditional devices, and must continuously submit algorithm update data.

Expiration Risk: AI devices relying on static datasets that fail to complete compliance upgrades by the end of 2025 will have their registrations automatically invalidated.

Exemptions and Exceptions

Certain Class I and II devices are exempt from 510(k) submissions (e.g., exemptions listed in 21 CFR 862-892.9).

Combination products (e.g., drug-eluting stents) are classified based on their primary component and may need to comply with both drug and device regulations.

III. Classification Inquiry and Compliance Recommendations

Inquiry Tools

FDA Classification Database: Query specific classifications, regulatory numbers, and exemption conditions by entering device names or product codes.

CDRH Learning Platform: Offers video modules and webinars to help companies understand classification logic.

Compliance Strategies

Preliminary Classification Confirmation: Use the FDA’s AI/ML Medical Device Decision Tree Tool to conduct initial risk grading and identify high-risk features (e.g., dynamic learning, patient-specific adaptation).

Professional Support: Collaborate with Contract Research Organizations (CROs) to develop global registration roadmaps, prioritizing FDA core markets.

Dynamic Tracking: Monitor FDA official websites and industry media to adjust compliance strategies promptly (e.g., 2025 UDI requirements for combination products).

IV. Case References

Glucose Meter Classification: Typically classified as a Class II medical device (product code NGH), requiring a 510(k) submission. If equipped with Bluetooth/Wi-Fi functionality or AI-assisted diagnostics, additional compliance with wireless medical device standards or separate classification assessments is required.

AI Chest X-ray Diagnostic System: Due to insufficient training data samples from African patients (<5%), misdiagnosis rates surged by 40% in Africa, highlighting the limitations of static datasets. A dynamic data update mechanism is required to meet Class III device requirements.