Demonstrating robust clinical evidence is essential for EU MDR and IVDR compliance. For most manufacturers, this begins with a structured and reproducible literature search, the cornerstone of a clinical evaluation.
An effective literature search identifies existing safety and performance data, benchmarks the state of the art, and supports claims about device equivalence or similarity. Poorly planned searches can result in insufficient clinical evidence, rejection of clinical evaluation reports and/or audit findings, all of which can lead to delays in obtaining certification and/or placing device on the market.
This blog outlines how to conduct a literature search that meets regulatory expectations, aligns with MDCG and IMDRF guidance, and stands up to scrutiny from notified bodies.
Understanding the Role of a Literature Search
A literature search systematically gathers published information, journal articles, books, conference papers, and regulatory guidance relevant to a specific medical device or indication.
Under MDR (EU) 2017/745 and IVDR (EU) 2017/746, manufacturers must provide evidence that:
- Their device performs as intended and achieves its clinical benefits.
- Identified risks are acceptable when weighed against benefits.
- The device aligns with the current state of the art (SOTA).
A compliant search facilitates identifying and critically appraising existing data whether from Device Under Evaluation (DUE), similar or equivalent devices (SEDs) or from the literature on the disease, technology, or clinical use.
Planning the Search
A structured Clinical Literature Search Plan (CLSP) is mandatory for a defensible clinical evaluation. Before searching, define the following elements clearly and document them within your Clinical Evaluation Plan (CEP):
Purpose and scope
Determine whether the search will:
- Establish SOTA for the target condition or technology.
- Identify Similar or Equivalent Devices (SEDs) for comparison.
- Support Safety and Performance (S&P) claims for the Device Under Evaluation (DUE).
Key search parameters
Include:
- Keywords and phrases based on device technology, indication, and intended use.
- Databases and sources (e.g. PubMed, Embase, Cochrane Library, regulatory repositories).
- Inclusion and exclusion criteria e.g types of studies, publication timeframe, and language etc.
- Appraisal methods for assessing quality and relevance.
Document these elements clearly. A search that is not reproducible or transparent may be challenged during technical documentation review.
Performing the Search
Once the plan is established, conduct the search systematically.
Use recognised methodologies
Frameworks such as PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) or PICO (Population, Intervention, Comparator, Outcome) help ensure a structured and reproducible process.
Constructing search strings
Use Boolean operators (AND, OR) and truncation symbols to combine and refine terms. For example:
(“knee implant” OR “orthopaedic prosthesis”) AND (“safety” OR “performance”) AND (“clinical trial” OR “observational study”)
Test your strings to evaluate sensitivity and adjust as needed. Avoid overly narrow criteria that could exclude relevant data or excessively broad terms that return unmanageable results.
Assessing results
Review abstracts first, then assess full papers for relevance and quality. Document reasons for inclusion or exclusion and track each decision to maintain transparency.
Reporting and Appraisal
The Clinical Literature Search Report (CLSR) should detail your search methodology, results, and appraisal process.
Essential components
- Search objectives and scope.
- Databases and date ranges used.
- Complete search strings.
- Summary of search results and study types identified.
- Inclusion/exclusion rationale.
- Appraisal method and weighting system.
Use recognised critical appraisal frameworks such as Appendix F of IMDRF MDCE WG/N56:2019 or relevant MDCG 2020-6 guidance to evaluate the strength and relevance of each source.
A hierarchical contribution of evidence outlined in Appendix III of MDCG 2020-6 ensures that peer-reviewed clinical data, post-market surveillance, and real-world evidence are appropriately weighted.
Best Practice Tips for MDR and IVDR Compliance
- Review all available information. Understand the full clinical and technological landscape before defining your scope.
- Tailor your inclusion criteria. Avoid generic lists, design criteria specific to your device and purpose.
- Perform pilot searches. Test keyword combinations to refine results before conducting the final search.
- Ensure reproducibility. Auditors often request evidence that another reviewer could replicate your process.
- Include paid or restricted papers. If relevant data sit behind paywalls, seek access rather than exclude them.
- Record search limitations. Transparency about potential gaps strengthens credibility during notified body review.
- Use recognised appraisals. Align with frameworks such as IMDRF N56 and MDCG 2020-13 to ensure traceable quality grading.
Common Pitfalls
- Overly restrictive filters: Limiting study types or timeframes can unintentionally exclude critical safety data.
- Relying on a single database: Comprehensive searches require multiple sources to avoid bias.
- Neglecting documentation: Missing records of search decisions or quality assessments can lead to non-conformities.
- Using inconsistent terminology: Ensure all terms, device name, technology, indication are consistently applied across documents.
Useful Regulatory Resources
- MEDDEV 2.7/1 Rev. 4 – Clinical Evaluation: A Guide for Manufacturers and Notified Bodies.
- IMDRF MDCE WG/N56:2019 – Clinical Evaluation guidance on sufficient clinical evidence.
- MDCG 2020-6 – Guidance on clinical evidence for legacy devices.
- MDCG 2024-10 – Clinical evaluation of orphan medical devices.
- MDCG 2025-5 – Performance studies under IVDR.
These resources provide the reference points auditors expect manufacturers to cite when defending their literature search process.
Call to Action
LFH supports MedTech manufacturers in developing compliant clinical evaluation strategies under MDR and IVDR. From literature search planning to report preparation and appraisal, our regulatory experts ensure your clinical evidence withstands notified body scrutiny and aligns with the latest EU and IMDRF guidance.
What is the purpose of a literature search in clinical evaluation?
It provides objective evidence of safety, performance, and clinical benefit, supporting the device’s compliance with MDR or IVDR requirements.
How often should a literature search be updated?
Typically every 1–3 years, or sooner if there are significant technological or clinical developments.
Can manufacturers use their own inclusion/exclusion criteria?
Yes, but the rationale must be justified, documented, and aligned with the search purpose.
What happens if the literature search is incomplete?
An incomplete or poorly documented search can result in notified body findings, delayed certification, or rejection of clinical evaluation reports.
