Chapter 1

The Definitive Taxonomy of Medical Device Safety Events

Medical Device Vigilance Manual

Adverse Event vs. Incident — Fundamental Distinction

Adverse Event (AE)

Definition: Any untoward medical occurrence — includes patient injury, device malfunction, and use error
Causality: Temporal association only; no causal relationship required
Scope: Broader — any event during device use regardless of cause
Example: Patient using a wearable monitor develops skin irritation
vs.

Incident / Serious Incident

Definition: A device-related event that led to or could lead to death, serious injury, or serious public health threat
Causality: Device contribution suspected or confirmed
Scope: Narrower — requires device involvement + serious outcome or malfunction
Example: Ventilator software glitch causes intermittent apnea episodes

Event Classification Hierarchy

Hover over each box for details

AE
Adverse Event
Any untoward occurrence during device use
Includes device malfunction, use error, patient injury, and near-misses. No causal relationship to the device is required at this stage.
Incident
Reportable Incident
Malfunction, injury, or near-miss with recurrence risk
Includes any malfunction that would be likely to cause death or serious injury if it were to recur. The "would likely recur" criterion is unique to devices.
Serious Incident
Serious Incident (EU MDR Art. 2)
Death, serious deterioration, or public health threat
Directly led to, might have led to, or might lead to death, serious deterioration of health, or serious public health threat. Triggers 2–15 day expedited reporting.
FSCA
Field Safety Corrective Action
Manufacturer action to reduce risk of serious incident
Any corrective action taken by the manufacturer to reduce the risk of death or serious deterioration of health associated with a device already on the market (recalls, updates, user notifications).

Seriousness Criteria — Reporting Thresholds

Death

Any incident resulting in the demise of a patient, user, or third party

Life-Threatening

Patient at immediate risk of death at the time of the event

Serious Deterioration of Health

Permanent impairment or injury requiring medical/surgical intervention

Serious Public Health Threat

Imminent risk of death or serious injury requiring prompt remedial action

Reportable Malfunction

Device failure that did not cause harm but would likely do so if it were to recur

Near-Miss / Use Error

User interaction failure that could lead to harm — requires HFE assessment

Device-Specific: The "Would Likely Recur" Criterion

Unlike pharmaceuticals, medical devices must report malfunctions that did not cause harm but would likely do so if repeated. A software glitch in a ventilator corrected by a backup alarm still requires reporting because the malfunction could recur when the backup is unavailable.

IMDRF Adverse Event Terminology — 7 Annexes

The multi-perspective coding framework for device incidents

A

Medical Device Problem

Captures the observed malfunction or performance issue

e.g., A0401 - Break, A0501 - Material Deformation
B

Type of Investigation

Codes the technical evaluation method applied

e.g., B01 - Testing of Actual Device, B02 - Testing of Similar Device
C

Investigation Findings

Describes objective results of the device analysis

e.g., material fatigue, software logic error, contamination
D

Investigation Conclusion (Root Cause)

Codes the determined root cause of the failure

e.g., D0102 - HFE: Device Difficult to Operate, D0107 - Cybersecurity
E

Health Effects

Clinical signs and symptoms, often mapped to MedDRA Preferred Terms

e.g., thermal burn, pneumothorax, allergic reaction
F

Health Impact

Categorizes the outcome for the patient

e.g., F01 - Death, F02 - Serious Injury, F05 - No Consequences
G

Component

Identifies the specific device part involved in the failure

e.g., G01 - Battery, G03 - Sensor, G08 - Software Module

Regulatory Reporting — EU MDR vs. FDA 21 CFR 803

EU MDR (Regulation 2017/745)
Term: "Serious Incident" (Article 2(65))
Reporting form: Manufacturer's Incident Report (MIR)
Timelines: 2 days (public health threat), 10 days (death/serious), 15 days (other)
Database: EudraVigilance / EUDAMED
Responsible person: PRRC (Article 15)
FDA 21 CFR Part 803
Term: "MDR Reportable Event"
Reporting form: FDA Form 3500A / eMDR
Timelines: 5 days (remedial action), 30 days (death/serious injury/malfunction)
Database: MAUDE
Responsible person: Manufacturer's designated agent

Coding Matters for Signal Detection

If different technical reviewers code the same failure using different IMDRF Annex A terms (e.g., "break" vs. "fracture" vs. "material fragmentation"), the statistical signal of a manufacturing defect will be diluted across multiple codes, potentially masking a life-threatening design flaw.

Medical Device Vigilance Manual — Root Cause Analysis & Signal Detection · Chapter 1