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For biomedical and life sciences journals, inclusion in PubMed and MEDLINE represents a significant milestone in credibility and discoverability. However, the path to indexing involves meeting rigorous standards set by the U.S. National Library of Medicine (NLM). This comprehensive guide explains the different NLM databases, their requirements, application processes, and what journals need to prepare for successful indexing.
Understanding PubMed, MEDLINE, and PMC #
These three terms are often confused, but they represent distinct databases with different purposes and requirements:
PubMed #
PubMed is the free search interface providing access to over 36 million citations from biomedical literature. It includes:
- All MEDLINE content
- PubMed Central (PMC) content
- Citations from publishers who submit directly
- Citations from other NLM databases
PubMed is the broadest of the three, serving as the search portal rather than a curated index itself.
MEDLINE #
MEDLINE is NLM's premier bibliographic database, containing citations and abstracts from approximately 5,200 journals worldwide. MEDLINE journals undergo rigorous selection and are indexed with Medical Subject Headings (MeSH)—NLM's controlled vocabulary enabling precise searching. MEDLINE indexing is considered the gold standard for biomedical journals.
PubMed Central (PMC) #
PMC is NLM's free full-text archive for biomedical and life sciences journal literature. Unlike MEDLINE (which indexes citations and abstracts), PMC archives complete article content. PMC requires JATS XML submissions meeting specific technical standards.
Which Should You Apply For? #
The choice depends on your journal's situation and goals:
PMC First: Journals seeking full-text archiving and discoverability often start with PMC. PMC inclusion automatically adds citations to PubMed. Journals already indexed in MEDLINE generally pass PMC scientific review without additional evaluation.
MEDLINE: For maximum recognition and MeSH indexing, MEDLINE is the goal. MEDLINE-indexed journals are automatically eligible for PMC participation (for preservation requirements) without additional scientific review.
PubMed (Direct Submission): Some publishers submit citations directly to PubMed without MEDLINE or PMC inclusion. This provides visibility but without the prestige of MEDLINE selection or PMC archiving.
Pre-Application Requirements #
Before applying to either MEDLINE or PMC, journals must meet these baseline requirements:
Publication History #
NLM expects publishers to have at least a two-year history of quality scholarly publishing in life sciences. Exceptions may be considered if management and editorial staff have demonstrated experience at other organisations—but all other requirements still apply.
ISSN Registration #
The journal must have a properly registered ISSN with a confirmed record in the official ISSN International Centre Register. Both print ISSN (if applicable) and electronic ISSN should be registered.
Content Volume (PMC) #
For PMC applications, the journal must have published at least 25 peer-reviewed articles. This demonstrates sufficient content for evaluation and ongoing archiving commitment.
Scope Alignment #
Journal content must fall within NLM's collection scope—biomedical and life sciences. Journals outside this scope, regardless of quality, won't be considered.
Language Requirements #
Both MEDLINE and PMC have language guidelines:
- MEDLINE: Accepts journals in various languages but requires Roman script for references, names, and affiliations
- PMC: Primary content must be largely in English (except for MEDLINE-indexed journals, which PMC accepts regardless of language, and Spanish-language journals as of February 2023)
Preparing Your Journal for Indexing Applications?
Professional journal infrastructure—from website presentation to metadata quality—affects how evaluators perceive your journal. We help journals meet technical requirements and present themselves professionally.
MEDLINE Scientific Quality Criteria #
NLM's scientific quality review focuses on five critical elements. Note that in 2025, the Literature Selection Technical Review Committee (LSTRC) was terminated—reviews are now conducted by NLM staff and external consultants directly.
1. Scope and Coverage #
- Journal scope aligns with NLM collection and MEDLINE scope
- Content is primarily original research, reviews, clinical case reports, or similar scholarly material
- Coverage is appropriate for the stated scope—not too narrow or unfocused
2. Quality of Content #
- Scientific rigor in methodology and reporting
- Appropriate study designs for research questions
- Valid conclusions supported by presented data
- Contributions advance knowledge in the field
- References are current and relevant
3. Quality of Editorial Work #
- Clear, comprehensible writing
- Proper organisation and structure
- Quality of figures, tables, and supplementary materials
- Consistent formatting and style
- Thorough copyediting
4. Production Quality #
- Professional presentation
- Accurate metadata
- Consistent publishing schedule
- Timely publication
5. Audience and Purpose #
- Appropriate for biomedical research community
- Adds value beyond existing indexed journals
- International relevance (for MEDLINE's global audience)
PMC Scientific Quality Review #
PMC uses a similar multi-step evaluation process. At least two consultants—typically one doctoral-level researcher or physician and one medical librarian—review each journal. They evaluate articles from the last two years based primarily on scientific and editorial quality.
Journals already fully indexed in MEDLINE generally do not require additional scientific review for PMC.
Technical Requirements #
MEDLINE Technical Requirements #
Journals accepted for MEDLINE must:
- Supply citations to PubMed within six months of final publication
- Submit data via Secure File Transfer Protocol (SFTP) in PubMed XML format
- Consistently meet PubMed's technical quality standards
- Work with an XML provider (if new to PubMed, the provider must complete technical evaluation within six months)
PMC Technical Requirements #
PMC has stringent XML requirements:
- Full-text articles must be submitted in JATS XML format (NISO JATS Journal Publishing Tag Set recommended)
- XML must conform to an acceptable Document Type Definition (DTD)
- Files must meet PMC's Minimum Data Criteria
- Technical evaluation involves submitting approximately 25 sample articles
- Generated article presentation must accurately represent the version of record
Important: PMC's XML requirements are rigorous. Many journals work with specialized XML conversion services to meet these standards. Costs typically range from $1-3 per page for conversion.
Publisher Practices & Ethics Requirements #
NLM expects conformance with established industry guidelines:
Required Policies and Standards #
- Adherence to ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals
- Compliance with Principles of Transparency and Best Practice in Scholarly Publishing (joint statement by COPE, DOAJ, WAME, and OASPA)
- Clear publication ethics policies
- Conflict of interest disclosure requirements
- Human and animal research ethics compliance
- Informed consent policies
Research Reporting Guidelines #
NLM encourages adherence to reporting guidelines including:
- PRISMA for systematic reviews and meta-analyses
- CONSORT for clinical trials
- STROBE for observational studies
- Helsinki Declaration for human research
- Relevant discipline-specific guidelines
Website Requirements #
The journal website must provide:
- Links to editorial board with affiliations
- Editorial policies
- Peer review process description
- Conflict of interest policy
- Human and animal rights policies
- Informed consent policy
- Publisher information including management, qualifications, and publishing policies
Access and Preservation Requirements #
Electronic Journal Requirements #
- NLM must have immediate access to content at publisher or third-party website
- Content must be accessible without barriers
- Permanent preservation arrangements required (MEDLINE journals can use PMC for this requirement)
Preservation Options #
Acceptable preservation methods include:
- PubMed Central (PMC) archiving
- LOCKSS/CLOCKSS participation
- Portico
- Other recognised digital preservation services
Application Process #
MEDLINE Application Steps #
- Verify Pre-Requirements: Confirm ISSN, publication history, scope alignment
- Submit Application: Via the MEDLINE Publisher Portal
- Initial Screening: NLM checks completeness and pre-requirements
- Scope Review: NLM determines if journal meets collection and MEDLINE scope
- Scientific Quality Review: External consultants evaluate content
- Technical Evaluation: If recommended, verify XML provider readiness
- Access/Preservation Check: Confirm compliance with requirements
- Final Decision: Accept or reject with feedback
PMC Application Steps #
- Verify Pre-Requirements: ISSN, 25+ articles, scope, language
- Submit Application: Via PMC Publisher Portal
- Initial Screening: Completeness and requirements check
- Scientific Quality Review: If not already MEDLINE-indexed
- Technical Evaluation Checklist: Publisher completes checklist
- Sample File Submission: 25 representative articles in XML
- Technical Evaluation: PMC evaluates XML quality
- Final Decision: Accept for archiving or reject with feedback
Rejection and Reapplication #
Journals rejected during initial screening or scientific quality review are eligible to reapply after 24 months. Before reapplying, journals should:
- Address specific feedback provided by NLM
- Improve identified weaknesses in content or policies
- Build a stronger publication record
- Ensure all current requirements are met
Initial Screening Rejection Triggers: Systematic concerns with scientific rigor, editorial quality, editorial policies, authorship patterns (repeat authorship, editorial board authorship), or ethics policy enforcement will result in rejection without further review.
Ongoing Requirements for Indexed Journals #
Acceptance is conditional on maintaining standards:
MEDLINE Ongoing Requirements #
- Maintain scientific quality standards
- Supply quality citations to PubMed within six months of publication
- Follow industry best practices
- Maintain stated publishing schedule
- Notify NLM of journal or publisher changes
- Meet access and preservation requirements continuously
Publisher Compliance Issues #
NLM may place temporary holds on publishers due to problems with journals. Serious violations of best practices can result in:
- Cessation of indexing for affected journals
- Rejection of new applications from the publisher
- Minimum three-year embargo on eligibility for NLM databases
PubMed/MEDLINE Readiness Checklist #
Pre-Application Requirements #
☐ Journal has ISSN registered with ISSN International Centre
☐ At least 2 years of publishing history (or documented staff experience)
☐ Content falls within biomedical/life sciences scope
☐ At least 25 peer-reviewed articles published (for PMC)
☐ Language requirements met (English content or Roman script references)
Scientific Quality #
☐ Articles demonstrate scientific rigor and valid methodology
☐ Content advances knowledge in the field
☐ Writing is clear and comprehensible
☐ Figures and tables are high quality
☐ References are current and relevant
☐ Consistent editorial standards maintained
Website & Policies #
☐ Editorial board listed with affiliations
☐ Peer review process described
☐ Publication ethics statement present
☐ Conflict of interest policy stated
☐ Human subjects research ethics policy
☐ Animal research ethics policy (if applicable)
☐ Informed consent policy
☐ Publisher information and contact details
☐ Open access/copyright policies clear
Technical Readiness #
☐ XML provider identified or XML capability established
☐ JATS XML production capability (for PMC)
☐ Metadata quality is accurate and complete
☐ DOIs assigned to articles (recommended)
☐ Full-text access available without barriers
Preservation & Access #
☐ Digital preservation arrangement in place or planned
☐ Content accessible to NLM for evaluation
☐ Backfile complete and accessible
Best Practices Compliance #
☐ ICMJE Recommendations followed
☐ COPE guidelines adherence
☐ Relevant reporting guidelines implemented (PRISMA, CONSORT, etc.)
☐ No predatory publishing characteristics
How Altechmind Can Help #
While indexing decisions rest entirely with NLM, proper infrastructure and presentation support successful applications:
Technical Infrastructure #
- OJS Configuration: Professional OJS setup with proper metadata fields, author guidelines integration, and editorial workflow configuration
- OAI-PMH Setup: Proper Open Archives Initiative Protocol for Metadata Harvesting configuration enabling metadata harvesting by indexing services
- Metadata Optimization: Ensuring article metadata is complete, accurate, and properly structured for discoverability
Website & Presentation #
- Policy Page Development: Creating comprehensive, professionally presented policy pages that evaluators expect to see
- Editorial Board Display: Proper presentation of editorial team with affiliations
- Journal Identity: Professional presentation of ISSN, scope, publisher information
Hosting & Reliability #
- Server Configuration: Reliable hosting ensuring consistent access for evaluators
- SSL/Security: Proper security configuration
- Email Deliverability: Ensuring editorial communications work reliably
Important Disclaimer #
This article provides general guidance based on publicly available NLM documentation as of December 2025. NLM policies, criteria, and processes may change without notice. Always consult the official NLM/MEDLINE and PMC documentation for current, authoritative requirements:
- MEDLINE: nlm.nih.gov/medline
- PMC: pmc.ncbi.nlm.nih.gov
Altechmind Technologies provides technical services for journal infrastructure. We are not affiliated with NLM, and our services do not guarantee indexing acceptance. Indexing decisions are made solely by NLM based on their evaluation criteria.
