Design verification, or Design Verification in English usage, is the documented evidence that the design outputs of a medical device meet the specified design inputs. ISO 13485 regulates it in section 7.3.6 and requires that verification be carried out according to planned arrangements and that its results, along with necessary actions, be maintained as records. It is thus a comparison between requirements and the realized solution at the specification level, and not yet a statement about suitability for the user, which is assigned to the design validation of medical devices. The existing glossary entry on validation addresses pharmaceutical validation subjects and does not cover this product-related evidence.
Verification Planning and Acceptance Criteria
Verification requires verifiable inputs. Design inputs according to ISO 13485 Section 7.3.3 must therefore be formulated in such a way that they are measurable, unambiguous, and consistent; qualitative requirements such as good usability must be operationalized or assigned to validation. For each requirement, a verification method is defined, usually testing, analysis, calculation, simulation, inspection, or comparison with a proven design. The verification plan specifies the test object, test samples, test equipment and its calibration status, test conditions including pre- and post-treatment such as aging, sterilization or transport simulation, acceptance criteria, and the evaluation of the results. If requirements are derived from harmonized or recognized standards, the test procedures specified therein are adopted, for example, for electrical safety, electromagnetic compatibility, packaging and sterile barrier systems, or mechanical strength and fatigue strength.
Sampling Logic and Traceability
A frequently underestimated point is statistical justification. ISO 13485, in section 7.3.6, explicitly requires verification plans with methods, acceptance criteria, and, where appropriate, statistical techniques with a rationale for sample size; this means deriving sample sizes, confidence levels, and reliability requirements from the risk of the respective requirement rather than from convention. Safety-critical characteristics regularly require higher levels of evidence than functional comfort features. Secondly, traceability must be complete: every design input must be assigned to a design output and a verification record, usually via a traceability matrix, which also maps the link to control measures from risk management. If an intended purpose requires connection or interface with other medical devices, verification according to ISO 13485 Section 7.3.6 must also be performed in the connected state. Unmet acceptance criteria are not to be remedied by re-evaluating the criteria, but by deviation handling, design change, or justified adjustment of the inputs with renewed evaluation. All evidence is maintained in the design history file of a medical device.
Distinction from Validation, Process Validation, and Incoming Inspection
Verification checks against the specification, validation against user needs and intended purpose. The practical consequence is that a fully passed verification does not rule out an unsuitable design if the inputs incompletely captured the need; conversely, a successful user study cannot replace missing specification evidence. Verification differs from process validation according to section 7.5.6 in that it considers the product, not the capability of a process; from verification of purchased products according to section 7.4.3 in that the latter determines the conformity of a delivery with purchasing specifications and makes no statement about the design. The ongoing final inspection in series production is also not design verification, but an acceptance test against already verified specifications.
Relevance for clinical trials
Design verification is the gateway to clinical investigation. Annex XV of Regulation (EU) 2017/745 requires preclinical data and design evidence in the study documentation; authorities and ethics committees review this evidence to determine whether the technical properties of the investigational product are substantiated and the residual risks for study participants are acceptable. Open verification points on safety-relevant characteristics are a typical reason for queries and cannot be made up for by clinical observation.
For study conduct, verification also provides the limits of permissible use, such as service life, load capacity, compatibilities, storage and transport conditions, and reprocessing cycles; these limits must be reflected in the clinical investigation plan, handling instructions, and investigator’s brochure. Changes to the investigational product during the study period trigger a renewed, scope-related verification and must be assessed for their impact on ongoing data collection. Full-service CROs like Mediconomics support manufacturers and sponsors in structuring the preclinical evidence required for study documentation, translating application limits into the clinical investigation plan and investigator’s brochure, and evaluating changes to the investigational product from a study perspective.
Frequently Asked Questions (FAQ)
What is the concrete difference between verification and validation?
Verification according to ISO 13485 Section 7.3.6 demonstrates that the design outputs meet the design inputs. Validation according to Section 7.3.7 demonstrates that the product meets user needs and its intended purpose under actual use conditions.
How many samples need to be tested?
There is no fixed number. ISO 13485 Section 7.3.6 requires, where appropriate, statistical techniques with a rationale for sample size in the verification plan; this must be derived from the risk of the respective requirement and the required confidence and reliability levels.
Can verification be performed by calculation?
Yes. In addition to testing, analyses, calculations, and simulations are permissible, as is comparison with a proven, demonstrably equivalent design, provided that the method and input data are justified and documented.
Regulatory References
- ISO 13485:2016, Section 7.3.6 – Design Verification
- ISO 13485:2016, Sections 7.3.3, 7.3.4, 7.3.7 and 7.3.10 – Design Inputs, Design Outputs, Design Validation, Design History File
- ISO 13485:2016, Sections 7.4.3 and 7.5.6 – Verification of Purchased Product, Process Validation with justified sample sizes
- Regulation (EU) 2017/745, Annex II Sections 4 and 6.1 – Demonstration of safety and performance requirements, preclinical data
- Regulation (EU) 2017/745, Annex XV Chapter II – Documentation for clinical investigations
