MedlinePlus Connect: 10 Years of Linking Electronic Health Records to Consumer Health Information

Guest post by Jennifer Jentsch, MLS, Project Manager, MedlinePlus Connect, National Library of Medicine

NLM is celebrating the 10th anniversary of MedlinePlus Connect, a free service that links electronic health records (EHRs), patient portals, and other health IT systems to relevant, authoritative, and up-to-date health information from NLM’s MedlinePlus health information resource and other NIH websites. A look back over the past 10 years highlights opportunities that came together to create this successful NLM resource.

Development of MedlinePlus Connect

We know that having access to information empowers people. When it comes to a person’s health, information is fundamental in helping people learn about their conditions, medications, and treatment options, and helps them make more informed decisions about their health. We also know that to facilitate this understanding, health care professionals need to point the people they treat to trusted, accurate health information that is easy to understand. Quality information is an essential component of quality health care.

With the release of the MedlinePlus and MedlinePlus en español websites in the late 1990s, NLM quickly became a trusted source of quality online health information for the public. A decade later, a new health information need began to emerge. Health care providers were rapidly transitioning from paper health records to EHRs. The EHR system itself became a new platform for the delivery of health education, where both patients and providers could easily access explanatory resources about a diagnosis, medication or medical test. The sharing of trusted health information between provider and patient was migrating to an entirely electronic, yet personalized, environment.

In these emerging EHR systems, NLM saw an opportunity to leverage the rich resources of MedlinePlus and serve the public in a new way.   

The idea became reality with the launch of MedlinePlus Connect in 2010. NLM used the expertise of staff in data science, medical code systems, health data standards, and information technology to build this innovative service. The team created an Application Programming Interface (API) to seamlessly bring the rich consumer health resources of the MedlinePlus and MedlinePlus en español websites directly into EHRs. Tens of thousands of pages about diseases and conditions, medications and lab tests were now accessible for use in a new way. 

How It Works

MedlinePlus Connect is a free web application and web service that does not require registration to use. It works by accepting specific requests from EHR systems in a customized HTTPS format and responds with links to relevant information.

In the course of patient care, health care professionals assign medical codes for particular diagnoses, tests, procedures, and medications to the health records of patients. MedlinePlus Connect uses these codes to provide patient-specific health information to the EHR system.

As part of NLM’s commitment to health data standards, MedlinePlus Connect uses standard medical code systems like SNOMED and LOINC, and adheres to the Infobutton standard. To facilitate the connection with EHRs, NLM staff create “mappings” (or associations) between MedlinePlus content and standard medical coding systems used in EHRs. Today, MedlinePlus Connect supports half a dozen major code systems for diagnoses, medications, procedures, and medical tests, including ICD-9-CM, ICD-10-CM, SNOMED, and RxNorm.

MedlinePlus Connect Today and into the Future

Since its launch, MedlinePlus Connect has been employed by a wide array of users, including large and small EHR systems, health care networks and organizations, hospital systems, and mobile applications. The API has grown significantly in usage, in content, and in code mappings. (See our timeline infographic for important developments over the past 10 years.)

See how MedlinePlus Connect has grown over the past 10 years.    Image credit: Brenna Cox

Today, MedlinePlus Connect provides a robust service that can easily respond to more than 171,000 medical codes with relevant health information.  In 2020, MedlinePlus Connect received 252 million code requests from external systems.

An exciting new initiative is the integration of consumer health information from other NIH Institutes and Centers (ICs). In 2018, MedlinePlus Connect piloted a collaboration with the National Institute of Diabetes and Digestive and Kidney Diseases. The success of this collaboration led to the participation of two additional NIH Institutes: the National Institute on Aging and the National Cancer Institute . NLM is working with other NIH ICs in this effort to expand the scope of content in MedlinePlus Connect.

The next major development will be the addition of Current Procedural Terminology (CPT®) codes from the American Medical Association to expand access to information about medical procedures.

As MedlinePlus Connect enters a new decade, we can’t help but reflect on how the goals behind the service remain very much the same as they were when this service launched:  to deliver health information to the public in new and innovative ways, to reduce barriers in information access, and to support quality health care everywhere.

Interested in learning how to implement MedlinePlus Connect?  Read our documentation and contact us with questions. Sign up for the MedlinePlus Connect email list to keep up with developments and exchange ideas with other users.

Jennifer Jentsch, MLS, joined NLM in 2001 and has supported a variety of NLM health information products including PubMed, PubMed Central, and MedlinePlus. Since 2014 she has served as Project Manager for MedlinePlus Connect.

Upcoming Training Opportunity: University-based Training for Research Careers in Biomedical Informatics and Data Science

Guest blog by Valerie Florance, PhD, Director of NLM’s Division of Extramural Programs

Explore the Training

NLM’s Extramural Programs Division is a principle source of NIH funding for research training in biomedical informatics, applying approaches in computer and information science to challenges in basic biomedical research, health care, and public health administration. NLM’s support fundamentally shapes the education, training, and advancement of biomedical informatics nationally. For decades, NLM has sponsored university-based training for predoctoral and postdoctoral fellows to prepare them for research careers. These programs support NLM’s long-term investment strategy to help influence and impact the field of biomedical informatics and data science.

Last October, NLM published NOT-LM-21-001 in the NIH Guide for Grants and Contracts to allow potential applicants sufficient time to develop meaningful collaborations and responsive projects. This program, a model among NIH training programs, advances training with big data in biomedical informatics and produces interdisciplinary, researchers that fully comprehend the challenges of knowledge representation, decision support, translational research, human-computer interaction, and social and organizational factors that influence effective adoption of health information technology in biomedical domains. This notice was the first step in a year-long process that will result in new 5-year grant awards that begin in July 2022. You’ll find the notice outlines the expected timetable for publishing the funding opportunity announcement, accepting applications, reviewing them and making awards.

The solicitation for new applications will be published in the NIH Guide for Grants and Contracts in March with applications due in May. For those interested in applying for an NLM training grant for the first time, we encourage a review of the previous solicitation to get a sense of the data and programmatic descriptions that are required for a training grant application.

Because issuance dates for the next competition are estimates, it is also helpful to subscribe to the weekly Table of Contents emails from the NIH Guide for Grants and Contracts. The extra benefit of this weekly mailing is that it lists all new funding issuances from NIH plus important notices about policy changes.

A Strong Foundation

NLM’s training programs offer graduate education and postdoctoral research experiences in a wide range of areas including health care informatics, translational bioinformatics, clinical research informatics, public health informatics, and biomedical data science. Each of these programs offer a combination of core curriculum and electives. In the current 5-year cycle, seven programs also offer special tracks in environmental exposure informatics supported by NIH’s National Institute of Environmental and Health Sciences.

A decades-old project, the university-based training initiatives is one of NLM’s signature grant programs. NLM’s training programs have produced many leaders in the field of biomedical informatics. Past trainees have taken positions in academia, industry, small businesses, health care organizations, and government. Currently, NLM supports 200 trainee positions at 16 universities around the United States and provides funding each year for up to 40 short-term trainee positions that are used to help recruit college graduates to our field by providing introductory training and research opportunities. To develop a sense of community among the trainees, NLM brings its trainees together each year, apart from those falling within a pandemic year, for an annual conference hosted at one of the university sites.

You can find a map with links to descriptions of the current programs here. The website also provides links to information about past annual conferences – check out past agendas to get a sense of the broad scope of science across the field of biomedical informatics.

Attendees comparing notes at NLM Informatics Training Conference 2017 in La Jolla, California

Did you take part in this training? What was your favorite thing about this experience? What advice would you give to current students? How can we make the program even better?

 Dr. Florance heads NLM’s Extramural Programs Division, which is responsible for the Library’s grant programs and coordinates NLM’s informatics training programs. 

DOCLINE: Connecting Medical Libraries for 35 Years

Guest post by Lisa Theisen, Head of NLM’s Collection Access Section and Elisabeth (Lis) Unger, NLM DOCLINE Team Lead

It’s been 35 years since NLM’s interlibrary loan (ILL) request routing system, DOCLINE®, was launched with a goal of enabling medical libraries to get biomedical literature into the hands of people who need it as efficiently and quickly as possible. Today, DOCLINE continues to be used daily by nearly 2,000 hospital, academic, military, public, and other libraries that place approximately one million requests a year, including requests for newly published research not freely available online.

DOCLINE’s foundation and success stems from NLM’s collaboration with the Regional Medical Libraries of the Network of the National Library of Medicine (NNLM) to support resource sharing among the medical library community. Resource sharing through ILL means that participating libraries don’t have to own as many books and journals or collect as broad a range of topics because they can borrow from each other. Full participation is limited to libraries in the NNLM and Canada, but some international libraries use the system to place requests directly with NLM.

DOCLINE service is fast and use of the system is free. This service allows a wide range of libraries, including hospital libraries (which account for 60% of DOCLINE participants), to obtain articles for their patrons that are not in their own collections.

This is where DOCLINE fills a critical gap by connecting a wide network of librarians who are always ready to help each other out, often without charge. Without DOCLINE, access to literature outside of a library’s collection is severely curtailed.

When DOCLINE first launched on mainframe computers in 1985, finding a ‘copy’ of an article or a library with the right issue of a print journal was not as easy as performing a simple search online. If you had a modem and access to an NLM account, you might check SERHOLD, the NLM database of medical libraries’ serial holdings – or journal titles libraries report subscribing to. Then you could mail, or maybe fax, an ILL form to the library and request that they mail your library a photocopy of the article. 

Over the decades, DOCLINE evolved in response to technological advancements and user needs. Features and enhancements have been added to DOCLINE throughout the years to make the system faster and easier to use. DOCLINE has grown to include new ways to send copies of articles, such as emailing PDFs, and adapted to new ways that publishers offer content, including electronic journals and “epub ahead of print” articles found in NLM’s PubMed biomedical literature citation database, and borrowers now see alerts to free, full-text articles found in NLM’s PubMed Central (PMC) digital archive.

Around the turn of the century, DOCLINE 1.0 moved to the world wide web – at the same time email use was becoming more widespread. In 2003, DOCLINE 2.0 was released with a new user-friendly look and feel; in 2006 it was updated to allow a library to indicate “Urgent Patient Care” to expedite service for use in emergencies in the hospital setting. The latest version, DOCLINE 6.0, debuted in November 2018. The three core system components, 1) the user library records, 2) their collective biomedical journal listings, and 3) ILL requests, would still be familiar to a user of the original system, even though the website looks very different today. DOCLINE also includes indicators for supplementary data sets and journal embargoes which didn’t exist in its early days.

What made DOCLINE remarkable in 1985 and remains its most intricate, complex feature, is the efficient way in which requests are automatically matched to appropriate lenders based on their reported journal holdings. This ensures that DOCLINE’s average length of time to fill a request and the percentage of filled requests continues to be high compared to other ILL systems – advancing NLM’s mission of enabling biomedical research and supporting health care and public health. This means that clinicians who rely on medical librarians to obtain the most relevant and latest research articles cited in PubMed, for instance on COVID-19 treatments, can rely on DOCLINE.

Continued updates to DOCLINE underscore the commitment to advance NLM’s strategic goals to reach more people in more ways through enhanced dissemination and engagement, and to engage a wide range of audiences to ensure the “right information gets delivered to them at the right time.” For instance, in April of this year, a ‘Print Resources Available’ filter was added to the system to enable user librarians working remotely from home to connect with libraries that still had access to their physical collection.

In its 35-year history, over 65 million ILL requests have been completed by libraries using DOCLINE. NLM is proud to provide the system and values the work of libraries that generously and unflaggingly share with one another, making DOCLINE a system that has been widely embraced by the user community over the years. We are looking forward to what the next 35 years mean for DOCLINE – teleporting articles anyone?

Are you a part of the DOCLINE community? How has ILL helped you?

Lisa Theisen began serving as Head of the Collection Access Section in the Public Services Division in March 2020. Ms. Theisen has been at NLM for 13 years, supporting DOCLINE and NLM’s Interlibrary Loan (ILL) operation.

Elisabeth Unger, MLIS, joined NLM’s Public Access Division, Collection Access Section, Systems Unit in 2008 to support DOCLINE and NLM ILL after working at the National Agricultural Library. In 2005 she became DOCLINE Team Lead where she was responsible for the latest redesign and relaunch of the esteemed system.

All for One…Health for All: The Role of Open Access, Evidence-Based Information to Improve Health for All Species

Guest post by Kristine M. Alpi, MLS, MPH, PhD, AHIP, OHSU Library, Oregon Health & Science University; Tova Johnson, MPH, MA, MLIS, OHSU Library, Oregon Health & Science University; and Heather K. Moberly, MSLS, AHIP, FHEA, PgCert (Vet Ed), University Libraries, Texas A&M University

Physical isolation arising from the COVID-19 pandemic has led many people to increasingly engage with the outdoor environment or bring companion animals into their lives as supports for their physical and mental wellbeing.

This connection among the health of humans, animals, and the environment exemplifies the One Health approach. 

One Health is not new, but it has gained new life amid rising concerns over COVID-19 and the environment in recent years. This model encourages collaboration across disciplines, with experts in human, animal, and environmental health, along with other specialties, to achieve better public health outcomes. While leaders often come from veterinary medicine or public health, anyone committed to keeping the world healthy is a potential partner in One Health. 


Providing high-quality, timely information to the people and professionals who need it most is critical to protecting the health of people, animals, and the environment. The FDA uses the term animal health literacy to provide the public with information about drug and food safety concerns that can have an impact on animals and humans. The joint NLM/FDA resource, DailyMed, includes drug listings approved for either humans or animals.

NLM’s MedlinePlus online health information resource provides robust information on animal-human interactions, but typically with a focus on those that threaten human health such as animal bites or zoonoses (diseases that can be passed between humans and animals). To get information from animal health experts, we can look to information providers such as veterinary educators to provide insights offering the interconnected One Health perspective.

Just as MedlinePlus relies, in part, on health professional societies to provide information on specialized care, veterinary medicine trains specialists in topics ranging from behavior to surgery, and provides information to support decision-making about large and small companion animal healthcare. Animal health information in multiple languages is not centrally coordinated, but the American College of Veterinary Surgeons is one example that offers information in Spanish as well as English.


Beyond personal experiences caring for animals at home or at work, One Health is a critical framework for providing timely, open, high-quality information during times of wildfires and natural disasters that can affect all species. Responding to natural disasters brings together teams who work primarily with humans and teams who typically work with animals. Many veterinary schools provide emergency preparedness education in addition to deploying veterinary emergency teams to respond to emergency situations that may be all species-focused or primarily a human health oriented mission. Central knowledge resources like the American Red Cross also provide apps and information to support people and pets during times of crisis.

Libraries who participate in the NLM-supported Network of the National Library of Medicine are essential resources for people seeking information online from trusted sources. Health sciences librarians, particularly the members of the Medical Library Association’s Animal and Veterinary Information Specialist Caucus, support the health of all species by addressing questions raised by people who live, work, and share the broader environment with companion animals and wildlife. These questions may come to public, community college, and university libraries who rely on free and direct access to high-quality resources written for a variety of audiences.

We recently presented Health Questions for All Species as a free webinar for the Oregon Reference Summit to highlight how to use NLM and other open access, evidence-based resources to address One Health questions. We acknowledged the value of regionally and culturally specific resources for populations who are particularly challenged by certain conditions or environmental exposures, and discussed similarities and differences in human and animal information sources, terminology and readability.

We hope this information expanded your awareness about how NLM and other information resources can promote One Health through an integrated approach to searching and addressing issues that impact humans, animals and our environment.

The One Health Commission is a great place for educational resources for teachers and learners who want to take another step towards Health for All.

Did you learn something new today? What can you do to contribute to One Health?

Kristine M. Alpi, MLS, MPH, PhD, AHIP, OHSU Library, Oregon Health & Science University and Adjunct Assistant Professor, Department of Population Health & Pathobiology, North Carolina State University.

Tova Johnson, MPH, MA, MLIS, OHSU Library, Oregon Health & Science University.

Heather K. Moberly, MSLS, AHIP, FHEA, PgCert (Vet Ed), Medical Sciences Library and department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University. Heather is a 2020 recipient of the Friends of the National Library of Medicine’s Michael E. DeBakey Library Services Outreach Award

The NIH Preprint Pilot: A New Experiment for a New Era

Guest post by Kathryn Funk, program manager for NLM’s PubMed Central.

Over the last several months, we have seen an increase in demand from the research and library communities for broader discovery and distribution of COVID-19 related literature, including early results posted as preprints. Preprints are complete, public drafts of scientific documents that are not yet peer reviewed. They are playing a key role in accelerating dissemination of research on the SARS-CoV-2 virus and COVID-19.

Recognizing the growing interest in preprints, NLM is today launching the first phase of the NIH Preprint Pilot, which will test the viability of making preprints searchable in PubMed Central (PMC) and, by extension, discoverable in PubMed, starting with COVID-19 preprints reporting NIH-supported research.

To be clear, NLM is not building a preprint server for NIH investigators, nor are we developing a comprehensive preprint discovery resource. Rather, through this pilot, we plan to add a curated collection of preprints from eligible preprint servers to our established literature resources. In doing so, our goal is to improve scholarly communications by accelerating and expanding the findability of NIH research results.

With the encouragement of NIH leadership, NLM has been exploring ways to leverage its literature databases to help accelerate the discoverability and maximize the impact of NIH-supported research via preprints. The planned pilot builds on guidance released by NIH in March 2017, which encouraged NIH investigators to use preprints and other interim research products to speed the dissemination of research and enhance the rigor of their work through public comments and new scientific collaborations.

Interest at NIH in the potential of preprints to improve scholarly communication long predates the 2017 guidance. As author Matthew Cobb recounts in “The prehistory of biology preprints: A forgotten experiment from the 1960s,”Errett C. Albritton, an administrator in the NIH Office of Research Accomplishments, established an informal network for the circulation of preprints and other scholarly communications by post to the group’s members. Although this initial “experiment” ended in 1967, support for the open sharing of scientific knowledge has continued at NIH through efforts such as the NIH Public Access Policy, which this pilot seeks to now complement.

Phase One Focus: COVID-19

In the first phase of the current pilot, NLM will make use of the NIH Office of Portfolio Analysis COVID-19 Portfolio tool to help identify preprints relating to the SARS-CoV-2 virus and COVID-19 pandemic. NLM will select preprints that either list an NIH-affiliated author or acknowledge NIH grant support. To accelerate discovery, preprints will be loaded and made searchable in PMC and PubMed once identified as in scope, without additional processing.  Standard XML versions will be loaded once the conversion process is completed. This workflow allows for rapid inclusion of preprints in the pilot without asking NIH investigators to separately submit them to PMC.

Recognizing that users come to NLM resources with varying levels of familiarity with scholarly communication practices, we want to make sure that researchers, clinicians, and the public can easily distinguish between preprints and peer-reviewed journal literature. Preprint records in PMC and PubMed will be flagged with large banners that clearly identify them as preprints. The banners will explain that the papers have not been peer reviewed and link to information about the pilot for additional context. Those who want to view only peer-reviewed journal literature will be able to exclude preprint records from search results in PMC using newly created filters.

We’ll closely monitor the early outcomes of the first phase of the pilot as we test and refine our workflows. We hope to be able to expand our scope in the next phase of the pilot to include the full spectrum of NIH-funded research, allow NIH investigators to identify their preprints through simplified reporting in My Bibliography, and establish more automated and faster curation workflows.

NLM will continually monitor the impact of the pilot on the scholarly communications landscape, including how research results are shared, discovered, disseminated, and reported, and evidence of increased awareness and emerging best practices around preprint sharing.

We expect the pilot will run for a minimum of 12 months to give us sufficient time to examine the use of preprints and their importance to scholarly communications in biomedical science. Feedback from stakeholders and lessons learned will inform future NLM efforts related to preprints.

PMC turned 20 in February, and its story over those two decades has been one of innovation, evolution and expansion, as we strive to build a collection at NLM that represents “the intellectual content and diversity of the world’s biomedical literature, data, and other research objects and information” and to foster open science practices. In launching this new preprint experiment in PMC, with an initial focus on COVID-19-related preprints, NLM hopes to continue to accelerate and expand access to relevant research in response to the ongoing public health emergency response efforts and to learn more about the impact of accelerated discovery and open sharing of research results on scholarly communications.

Tell Us What You Think!

We encourage you to learn more about the NIH Preprint Pilot and review the pilot overview and related FAQs.

As this new experiment unfolds, please feel free to send feedback to pmc-preprints@ncbi.nlm.nih.gov.

casual photo of Kathryn Funk
Kathryn Funk is the program manager for PubMed Central. She is responsible for PMC policy as well as PMC’s role in supporting the public access policies of numerous funding agencies, including NIH. Katie received her master’s degree in library and information science from The Catholic University of America.