DOCLINE: The Backbone of Medical Library Resource Sharing

Resource sharing is one of the oldest and most practical ideas in librarianship. No single library, however well-funded, can own every journal a researcher might need. This is especially true in medicine, where the literature is vast, expensive, and growing every day. To solve this problem, the National Library of Medicine (NLM) in the United States built a system that quietly powers thousands of medical document requests behind the scenes. That system is DOCLINE, and understanding how it works gives a clear picture of how modern inter-library loan (ILL) operates in the health sciences.

What is DOCLINE? 🔗

DOCLINE is the National Library of Medicine’s interlibrary loan request routing system. In plain terms, it is an automated platform that helps one library borrow journal articles and other biomedical materials from another library. Its core purpose is to improve access to biomedical literature for libraries in the Network of the National Library of Medicine (NNLM) and beyond.

The key word here is routing. DOCLINE does not store or transmit the articles themselves. Instead, it acts as an intelligent matchmaker: when a library needs an item, DOCLINE finds another library that owns it and is willing to lend it, then passes the request along. The actual article is delivered separately by the lending library. This is why DOCLINE is described as a request routing system rather than a document database.

It is also important to understand what DOCLINE is not. It is not an article purchasing mechanism. The system is built for reciprocal sharing among libraries that both borrow and lend, not for buying single articles from a vendor. The platform is available around the clock, every day of the week, with brief pauses on certain national holidays in the United States.

A brief history of the system 🔗

DOCLINE has served medical libraries since 1985, making it one of the longest-running automated ILL systems in the world. Over the decades it has gone through several major versions, each adding new capabilities. DOCLINE 5.0, released in 2014, for example, introduced electronic journal embargo data so the routing engine could automatically skip lenders who were not yet permitted to share a recent article. The current generation, DOCLINE 6, was a complete redesign launched in 2019 with a modernised interface and a Google-based sign-in process, available at docline.gov.

Who can use it and what it costs 🔗

The system is intended for reciprocal ILL among biomedical libraries in the United States and Canada, along with selected international participants. To join as a lending library, an institution generally needs a health sciences or biomedical collection and a willingness to lend from at least ten journals. Every participating institution is identified by a unique six-character code called a LIBID, which is required to place requests. For NNLM members there is no charge to participate in DOCLINE itself, although individual transaction charges vary from one lender to another.

How DOCLINE benefits medical libraries 🔗

The real value of DOCLINE lies in efficiency. Before automated systems existed, a librarian searching for an article would have to guess which institutions might hold a particular journal, then contact them one by one. DOCLINE removes that guesswork by automating both the search for a lender and the routing of the request.

The routing algorithm at the heart of the system 🔗

DOCLINE finds potential lenders through a routing algorithm that matches each request against the reported journal holdings of other libraries. The algorithm is what makes the service prompt and accurate. When a borrowing library submits a request, the system checks several conditions before sending it on. A request will only route to a library if that library actually reports owning the needed volume or year, supports the borrower’s preferred delivery method, is an active participant at the time, and is not on the borrower’s “do not route to” list.

Each library builds a routing table made up of ordered cells. The system works through these cells one at a time. Within a single cell, DOCLINE randomly selects up to a maximum of twenty libraries that match the request and tries them first. If none can fill the request, it moves to the next cell. This design spreads the lending workload fairly across the network instead of overloading a few large libraries, while still routing requests quickly enough that most are filled without needing to travel through many cells.

Library groups and FREESHARE 🔗

To make routing even easier, DOCLINE supports library groups: clusters of libraries that agree to follow a shared set of lending rules. The best-known example is FREESHARE, whose members lend to one another at no cost, meaning a zero base fee. By adding an entire group to a routing table cell, a librarian instantly widens the pool of potential lenders without having to list each institution individually. If the group’s membership changes later, the routing table updates automatically. This combination of intelligent routing and cooperative groups is what allows a request to be filled within hours rather than days.

EFTS: simplifying payment in medical inter-library loans 🔗

Finding a lender is only half the story. Lending libraries often charge a small fee for each article they supply, and managing thousands of these tiny charges through paper invoices and cheques would create enormous administrative work. This is the problem the Electronic Fund Transfer System (EFTS) was designed to solve.

EFTS is an online billing system for DOCLINE inter-library loan transactions. It collects an ILL charge from the borrowing library on behalf of the lending library and pays it to the lender, keeping a small transaction fee in the process. In effect, it works like a shared account ledger for the entire medical library community, so that institutions no longer have to bill and pay one another individually for every single article.

How EFTS works alongside DOCLINE 🔗

The two systems are tightly connected but separate. DOCLINE handles the matching and routing of requests, while EFTS handles the money. Once a DOCLINE transaction is complete, the details are transmitted automatically to EFTS, where the lending library can approve the charge and bill the borrower. This removes the need to create invoices and process reimbursement cheques, reducing administrative costs and improving cash flow for libraries.

EFTS was originally developed and operated by the University of Connecticut Health Center beginning in 1996. Its operations have since moved to the Medical Library Association (MLA), which now manages the platform for the community. Libraries can even set EFTS participation as a condition in their routing instructions, so requests only go to lenders who use the same billing system, keeping payment smooth from start to finish.

Loansome Doc: access for individual users 🔗

For most of its history, DOCLINE served libraries, not individuals. To extend access to doctors, researchers, and other end users, NLM ran a companion service called Loansome Doc. It allowed a registered individual to order the full text of an article directly from a searched citation, usually starting from PubMed, and have it supplied through a partner library. For health professionals without easy access to a large medical collection, this was a valuable bridge to the literature.

What replaced Loansome Doc 🔗

It is important to be accurate about the current state of this service. NLM retired Loansome Doc on 1 July 2019 because its use had been declining steadily since peaking around 2002. The service is no longer available. Its retirement reflects a broader shift in how people now reach medical literature. A large and growing share of biomedical research is freely available through PubMed and PubMed Central, and open-access policies have made many articles accessible without any ILL request at all. Individuals who still need a copyrighted article are now directed to work through their local or institutional library, which can place the request using DOCLINE or other ILL workflows on their behalf.

This evolution is a useful lesson for students of information services. A service is valuable only as long as it meets a real need. As open access expanded and search tools improved, the demand for a separate patron-ordering layer faded, and the system was retired rather than maintained out of habit. The underlying goal, connecting users to the literature they need, continues through newer and often free channels.

Taken together, DOCLINE and EFTS show how a well-designed network can turn a slow, manual chore into a fast, almost invisible process. The routing algorithm finds the right lender, library groups widen the pool, and EFTS settles the cost, all with very little human effort. For anyone studying information products and services, it is a clear model of how automation, cooperation, and shared standards combine to keep knowledge moving.

What do you think? If a similar routing-and-billing network were built for academic libraries in your own country, which subject areas would benefit the most? And as open access continues to grow, do you think traditional inter-library loan systems will remain essential, or slowly fade the way Loansome Doc did?

References

1. https://www.nnlm.gov/resources/docline
2. https://www.nlm.nih.gov/pubs/techbull/so14/so14_docline_release.html
3. https://www.nlm.nih.gov/docline/context_help/context_help_routing_choices.html
4. https://www.nlm.nih.gov/pubs/techbull/ma06/ma06_docline.html
5. https://www.mlanet.org/efts-general-information/
6. https://support.nlm.nih.gov/knowledgebase/article/KA-05294/en-us
7. https://www.nlm.nih.gov/pubs/techbull/jf19/jf19_loansome_doc_retire.html