--- title: "AE, Adverse Event | MedTech Terms" description: "Any untoward medical occurrence in a subject, whether or not related to the device. Plain-English Clinical & Trials definition for MedTech teams, with examples" lang: en json-ld: | { "@context": "https://schema.org", "@graph": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/adverse-event#term", "name": "Adverse Event", "alternateName": "AE", "description": "Per ISO 14155, an adverse event is any untoward medical occurrence, unintended disease or injury, or untoward clinical signs in subjects, users, or other persons, whether or not related to the investigational device.", "url": "https://medtechterms.com/terms/adverse-event", "termCode": "adverse-event", "inDefinedTermSet": { "@type": "DefinedTermSet", "name": "MedTech Terms", "url": "https://medtechterms.com/terms" } }, { "@type": "Article", "@id": "https://medtechterms.com/terms/adverse-event#article", "headline": "AE, Adverse Event", "description": "Any untoward medical occurrence in a subject, whether or not related to the device.", "url": "https://medtechterms.com/terms/adverse-event", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://medtechterms.com/terms/adverse-event" }, "about": { "@id": "https://medtechterms.com/terms/adverse-event#term" }, "articleSection": "Clinical & Trials", "inLanguage": "en", "keywords": "Adverse Event, AE, Clinical & Trials, medical device, MedTech", "author": { "@type": "Person", "name": "Christian Espinosa", "jobTitle": "Founder, Blue Goat Cyber", "url": "https://bluegoatcyber.com" }, "publisher": { "@type": "Organization", "name": "MedTech Terms", "url": "https://medtechterms.com" }, "isPartOf": { "@type": "WebSite", "name": "MedTech Terms", "url": "https://medtechterms.com" }, "datePublished": "2026-05-05", "dateModified": "2026-05-05", "citation": [ { "@type": "CreativeWork", "name": "ISO 14155 AE definitions", "url": "https://www.iso.org/standard/71690.html", "publisher": { "@type": "Organization", "name": "ISO" } }, { "@type": "CreativeWork", "name": "FDA - Clinical Trials and Human Subject Protection", "url": "https://www.fda.gov/science-research/science-and-research-special-topics/clinical-trials-and-human-subject-protection", "publisher": { "@type": "Organization", "name": "FDA" } }, { "@type": "CreativeWork", "name": "ClinicalTrials.gov", "url": "https://clinicaltrials.gov/", "publisher": { "@type": "Organization", "name": "NIH" } } ], "mentions": [ { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/iso-14155#term", "name": "ISO 14155", "url": "https://medtechterms.com/terms/iso-14155" }, { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/vigilance#term", "name": "Medical Device Vigilance", "url": "https://medtechterms.com/terms/vigilance" }, { "@type": "DefinedTerm", "@id": "https://medtechterms.com/terms/mdr-reporting#term", "name": "Medical Device Reporting (FDA)", "alternateName": "MDR", "url": "https://medtechterms.com/terms/mdr-reporting" } ] }, { "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://medtechterms.com/" }, { "@type": "ListItem", "position": 2, "name": "Terms", "item": "https://medtechterms.com/terms" }, { "@type": "ListItem", "position": 3, "name": "Clinical & Trials", "item": "https://medtechterms.com/terms?cat=Clinical%20%26%20Trials" }, { "@type": "ListItem", "position": 4, "name": "Adverse Event", "item": "https://medtechterms.com/terms/adverse-event" } ] }, { "@type": "FAQPage", "@id": "https://medtechterms.com/terms/adverse-event#faq", "mainEntity": [ { "@type": "Question", "name": "What distinguishes an adverse event from a serious adverse event (SAE)?", "acceptedAnswer": { "@type": "Answer", "text": "An adverse event is any untoward medical occurrence, while a serious adverse event meets specific criteria, such as leading to death, a serious deterioration in health, or requiring hospitalization, as defined by regulations like the EU MDR Annex XVI and FDA 21 CFR 803.3." } }, { "@type": "Question", "name": "Are all adverse events reportable to regulatory authorities?", "acceptedAnswer": { "@type": "Answer", "text": "No, not all adverse events are immediately reportable. 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Adverse Event [All terms](/terms) Clinical & Trials [Clinical Evidence](/ecosystems/clinical-evidence)[Post-Market & Safety](/ecosystems/post-market-safety)AE # Adverse Event Any untoward medical occurrence in a subject, whether or not related to the device. Reviewed by [Christian Espinosa, Founder, Blue Goat Cyber](/authors/christian-espinosa) Last reviewed May 5, 2026 ## Definition Per [ISO 14155](/terms/iso-14155), an adverse event is any untoward medical occurrence, unintended disease or injury, or untoward clinical signs in subjects, users, or other persons, whether or not related to the investigational device. What the regulation says Regulators like the FDA and those operating under the EU [MDR](/terms/mdr-reporting) mandate the reporting of adverse events to ensure patient safety and device effectiveness. The FDA’s 21 CFR Part 803 outlines medical device reporting requirements, while the EU MDR (Regulation (EU) 2017/745) details vigilance and [post-market surveillance](/terms/post-market-surveillance) obligations, including the reporting of serious incidents. [ISO 14155](/terms/iso-14155), specifically clause 7, provides guidance on recording and reporting adverse events in clinical investigations. ## What this means in practice AEs are the foundational unit of clinical safety reporting. Serious AEs (SAEs) and device-related AEs (ADEs/SADEs) trigger expedited reporting obligations. ## Examples - A patient implanted with a cardiac pacemaker experiences an unexpected infection at the implant site, which is identified as an adverse event. - During a clinical trial for a new glucose monitor, a participant reports a localized skin rash at the sensor application site, constituting an adverse event. - A user of an insulin pump experiences a hypoglycemic episode that requires emergency medical intervention, categorized as a serious adverse event. Common pitfalls - • Confusing an adverse event with a device malfunction that did not lead to an adverse clinical outcome, as these have distinct reporting pathways. - • Failing to initiate an investigation or report an adverse event due to a perceived lack of direct causal link to the device, as all untoward occurrences must be assessed. - • Delaying the reporting of serious adverse events (SAEs) beyond the mandated regulatory timelines, which can lead to non-compliance. - • Not adequately documenting the assessment of causality between the device and the adverse event, which is critical for regulatory review. - • Inconsistently applying definitions of "serious" across different studies or reporting jurisdictions, causing reporting errors. ## Frequently asked questions What distinguishes an adverse event from a serious adverse event (SAE)? An adverse event is any untoward medical occurrence, while a [serious adverse event](/terms/sae) meets specific criteria, such as leading to death, a serious deterioration in health, or requiring hospitalization, as defined by regulations like the EU [MDR](/terms/mdr-reporting) Annex XVI and FDA 21 CFR 803.3. Are all adverse events reportable to regulatory authorities? Who is responsible for identifying and reporting adverse events? ## Cross-references ### Used by Things that build on this term. - [ Medical Device Reporting (FDA)(MDR) ](/terms/mdr-reporting) ### Part of A larger framework or document this term belongs to. - [ ISO 14155 ](/terms/iso-14155) ### Contains Sub-elements or required artefacts of this term. - [ Serious Adverse Event(SAE) ](/terms/sae) ## Related terms Grouped by theme ### Editor's picks · Hand-selected related concepts [ Standards ISO 14155 Good clinical practice for clinical investigations of medical devices. ](/terms/iso-14155)[ Post-Market Medical Device Reporting (FDA)(MDR) FDA mechanism for receiving reports of device-related deaths, serious injuries, and malfunctions. ](/terms/mdr-reporting)[ Post-Market Medical Device Vigilance Reporting and management of serious incidents and field safety corrective actions. ](/terms/vigilance) ### Clinical Trials & Evidence · From this learning path [ Clinical & Trials Feasibility Study Small clinical study evaluating initial safety, usability, and design parameters of an investigational device. Adjacent lesson ](/terms/feasibility-study?from=clinical-trials-and-evidence)[ Clinical & Trials Surrogate Endpoint Biomarker or intermediate outcome used as a substitute for a clinical endpoint in regulatory decisions. Adjacent lesson ](/terms/surrogate-endpoint?from=clinical-trials-and-evidence)[ Clinical & Trials Adaptive Trial Design Trial design that pre-specifies opportunities to modify aspects (sample size, arms, endpoints) based on interim data. ](/terms/adaptive-trial?from=clinical-trials-and-evidence)[ Clinical & Trials Clinical Evaluation Report(CER) Documented assessment of clinical data demonstrating EU MDR conformity for a device. ](/terms/cer?from=clinical-trials-and-evidence) ### More in Clinical & Trials · Same category [ Clinical & Trials IDE Annual Progress Report Annual report sponsors must submit to FDA summarizing the progress of an approved IDE study, including enrollment, deviations, and adverse events. ](/terms/ide-annual-report) Cited by Where this term appears across MedTech Terms. Learning paths (1) - [Clinical Trials & Evidence](/paths/clinical-trials-and-evidence)Lesson 12 of 18 Ecosystems (2) - [Clinical Evidence](/ecosystems/clinical-evidence) - [Post-Market & Safety](/ecosystems/post-market-safety) ## Mentioned in recent activity 1 entry PubMed (1) [Global pharmacovigilance reporting: comparative analysis of adverse event obligations across five major regulatory authorities. ](https://pubmed.ncbi.nlm.nih.gov/42180407/) Frontiers in drug safety and regulation · 2026-01-01 ## Latest in MedTech [View all](/latest?term=adverse-event) Recent regulatory actions, publications, and trials matched to this term. Updated daily. - PubMed 2026-01-01 [Global pharmacovigilance reporting: comparative analysis of adverse event obligations across five major regulatory authorities. ](https://pubmed.ncbi.nlm.nih.gov/42180407/) Frontiers in drug safety and regulation ## Primary references 3 sources Link health: 3 verified · last checked 2026-06-20 ISO· 1 FDA· 1 NIH· 1 1. [1 ISO 14155 AE definitions Verified ISO · iso.org ](https://www.iso.org/standard/71690.html) 2. [2 FDA - Clinical Trials and Human Subject Protection Verified FDA · fda.gov ](https://www.fda.gov/science-research/science-and-research-special-topics/clinical-trials-and-human-subject-protection) 3. [3 ClinicalTrials.gov Verified NIH · clinicaltrials.gov ](https://clinicaltrials.gov/) Inline markers like \[1\] jump to the matching reference above. Sponsor note ### Clinical evidence intersecting with device security? We support clinical-stage MedTech teams whose investigational devices touch patient data or hospital networks. [Book a 30-minute discovery session](https://go.bluegoatcyber.com/meetings/blue-goat-cyber/discovery-session) - No obligation - Expert-led from minute one - NDA available on request MedTech Terms is a community resource sponsored by [Blue Goat Cyber](https://bluegoatcyber.com). Definitions are independent of any vendor. On this term Category Clinical & Trials Acronym AE Sources 3 Updated 5/5/2026 [Compare with another term](/compare?a=adverse-event) Learn in 60 seconds Card Lesson Quiz Any untoward medical occurrence in a subject, whether or not related to the device. - · AEs are the foundational unit of clinical safety reporting. - · Serious AEs (SAEs) and device-related AEs (ADEs/SADEs) trigger expedited reporting obligations. Remember this Watch out: Confusing an adverse event with a device malfunction that did not lead to an adverse clinical outcome, as these have distinct reporting pathways. Related terms - [ISO 14155 ](/terms/iso-14155) - [Medical Device Vigilance ](/terms/vigilance) - [Medical Device Reporting (FDA)(MDR) ](/terms/mdr-reporting) You may also need Auto-suggested from Clinical & Trials and shared keywords. - [Serious Adverse Event(SAE) ](/terms/sae) - [IDE Annual Progress Report ](/terms/ide-annual-report) - [Investigator Brochure(IB) ](/terms/investigator-brochure) - [Unanticipated Adverse Device Effect(UADE) ](/terms/uade) - [Clinical Investigation Plan(CIP) ](/terms/cip) - [Decentralized Clinical Trial(DCT) ](/terms/decentralized-clinical-trial) [All Clinical & Trials terms](/terms?cat=Clinical%20%26%20Trials) From the Blue Goat network Related resources and services on this topic. - [ MedTech Launchpad MedTech funding rounds, accelerators, and launch resources. ](https://medtechlaunchguide.com) MedTech Terms An authoritative, plain-language reference for the regulatory, quality, cybersecurity, and software terms that shape modern medical devices. 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