Originally Published MDDI March 2005

March 1, 2005

9 Min Read
Bridging the Gap: Medical Device Communication with XML

Originally Published MDDI March 2005


Bridging the Gap: Medical Device Communication with XML

XML has the potential to make widespread improvements in data management for the medical device and healthcare industries. The only problem is, it's just not there yet.

Brendan Gill

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XML is in its middle years, and it has yet to hit its stride. XML, which stands for extensible markup language, is designed to make data transfer easier because it is not platform dependent. A computer language too new to be widespread, it is too useful to ignore.

A number of hospitals and medical device manufacturers are using XML, but a majority have yet to adopt the technology. The reasons are varied, but familiar. Upgrade costs, worries about compliance, and the healthcare industry's usual cautiousness are some of them. According to the 2004 HDMA Industry Profile and Healthcare Factbook, “18% of distributors and 6% of manufacturers are using XML to process business information electronically.”

Because of the issues dealing with life and death in the medical device industry, “engineering style is extremely conservative,” says Bob Van Andel, president of Allegro (San Jose), a software and database management company that has developed an XML framer/parser. “Once [XML's effectiveness] has been proven, once some users stick their necks out and see that there are some benefits, you'll find people using it more.”

This article examines the potential of XML and explores how device manufacturers and the healthcare industry can take advantage of its flexibility.

What is XML?

XML has been around since the late 1990s, when it was created as a way to send highly structured documents over the Internet. A structured document includes both content and its context. That is, it contains text, photos, or other information, and markers as to what function that information serves in the document itself. In other words, XML tags make a distinction between text that serves as a footnote and text that is structured as a paragraph.

XML was created as an application of SGML, or standard generalized markup language. Technically, XML is not a language designed to “do” anything. It is simply a markup language designed to recognize the different parts or structures in a document.

Figure 1. XML is a platform-independent computer language that can ease the flow of information between different computer systems (click to enlarge).

Both computers and the human eye can read XML. XML enables programmers to set their own tag definitions, thereby not limiting the tags to formatting rules. Because the language is not based on formatting rules, it can be read by a variety of systems.

“At the heart of it, XML enables companies to take information from one system and provide it to another system,” says Marcus Yoder, vice president of industry marketing for Agile Software (San Jose), a software developer for product life cycle management. “You can take any portion of the information out of one system and repurpose it, without hardwiring and taking a lot of IT time to reformat.”

What Does It Look Like?

Characteristics of XML include correct nesting, attributes in quotes, null elements, and matching tags. XML documents are composed of elements that have starting and ending tags similar to those used in HTML, the markup language for publishing Web documents. Two examples would be and . In between the elements is the document's content. In XML format, a document containing the following information “Hi, my name is John Smith,” would look like this:


my name is John Smith.

No, It's Not Just Like HTML. Although there are similarities, crucial differences exist between XML and HTML. HTML features preset tags that define the information it transmits. In XML, however, the programmer can determine the tags. XML is a metalanguage, which is a language that describes other languages. This aspect of XML programming makes it possible for documents to be read by different systems. However, when writing in XML, code writers must be careful. The language is case sensitive, so the tags and do not mean the same thing.

XML documents are easier to read because there are no permanent semantics in place. XML documents are instead defined by the applications that handle them or by style sheets. Style sheets are applications that specify how an XML document is to be read, giving it form and context. A real-world example would be taking the editor's content, combining it with MD&DI's style sheet, and producing a version of the magazine.

XML Advantages for Medical Device Companies

One of the principal advantages of using XML is that it enables companies to collaborate easily. With XML, companies have a lingua franca to communicate with each other. In other words, companies don't have to reformat their bills of material when they send a work order to another company. Information can be exchanged without both companies having the same software, e.g. Excel.

This makes information exchange easier and decreases the risk of information being lost over shared files, says Brian Sohmers, director, product strategy and management for Agile.

“If you have two companies collaborating,” says Sohmers, “and one is responsible for product design and the other for building the product, by using [XML] the company responsible for manufacturing will be able to understand exactly what the designer wants to do.

“When you had a dialogue with another company before XML,” he adds, “it might be like someone speaking Spanish to someone who only speaks English.”

Product development benefits from using XML. Its data transfer capabilities make it possible for devices to communicate and interoperate in a way not possible with other software languages. For example, computers called programmers can talk to implanted medical devices and relay the information to a physician's office, says Reggie Groves, vice president and general manager of patient management at Medtronic (Minneapolis).

“Then that data might move from the programmer to many other systems,” Groves says. “It might move to a clinical research system that we have in-house, or it might move to a physician's practice management system…. Once we put it in XML format, we are able to put [information] in many disparate places very quickly.”

Despite its advantages, XML is not widely used in the medical device manufacturing industry. The reasons are those typical for why medical device makers are slow to adopt any new technologies.

“There's no compelling reason to change,” says Norman Daoust, a former HL7 expert at Partners HealthCare Systems (Boston). “In the healthcare industry, we've found that vendors will do whatever clients ask them to. So, until there is a lot of demand to support [XML], vendors have no incentive to change their systems.”

XML Advantages for Hospitals

XML is particularly well suited to hospital information exchange. Because of XML's adaptability, it's easier to access data from other healthcare organizations and insurance companies (see Figure 1). The time saved can be critical. For instance, if a patient's health records noting allergies, blood type, and surgery history are formatted with XML, they can be accessed more quickly in the case of an emergency. The records are available electronically and thus do not need to be faxed over from other organizations.

Data are more portable with XML, says Steve Flammini, director of clinical systems development at Partners HealthCare Systems, an integrated system of healthcare providers. The only obstacle to this level of information integration is getting healthcare-related organizations to cooperate in implementation. “The hard part is not the technology—it's easy to get computers to send the right [information],” says Flammini. “The hard part is gaining industry consensus to come up with standard markups.”

Using XML can also help hospitals comply with regulations, says Lindsy Strait, CTO of healthcare for SeeBeyond (Monrovia, CA), a provider of integrated platforms for enterprise application integration development. XML facilitates compliance with HL7 and the Health Insurance Portability and Accountability Act (HIPAA) of 1996. According to its Web site, www.hl7.org, HL7's mission is to “provide standards for the exchange, management, and integration of data that support clinical patient care and the management, delivery, and evaluation of healthcare service.” HIPAA requires that health organizations collaborate in electronic form. XML is a perfect fit for HL7's mission, Strait says. “It's ideal for service-oriented architectures. XML serves a pent-up demand for collaboration and efficiency.”

Data flow is also improved by XML. Information that is faxed or e-mailed has to be reentered into the hospital's database, which can be costly and time-consuming. With XML-encoded documents, information can be sent directly and integrated immediately.


The growing importance of privacy in the medical device manufacturing and hospital sectors is another issue that makes it likely the acceptance of XML will improve. XML's tagging for metadata gives sensitive information a greater degree of security. For example, says Strait, a patient's HIV test results can be coded using XML so that only the necessary personnel can view them. “You can take specific information and isolate it and manage it how you want,” says Strait. “That way, the only ones who can see this information are the right people.”

XML has a signature capability that helps to secure privacy. With digital signatures, access can be restricted and information can be encrypted to prevent tampering. To maintain document integrity, a trail can also be created that records how a document has been modified, by whom, and when.

The Cons of XML

XML is not without its problems, however. Enormous overhead can be produced if it is overused, up to 400% in contrast with other syntax transfers. It is a verbose language that requires thousands of bytes for even the tiniest bit of information. Too much XML documentation can cause servers to overload and make data retrieval maddeningly slow. “It's an insidious thing,” says Strait. “I've seen it where getting a [document] to come up can take 5–12 minutes.”

This aspect of XML can make it difficult to use for real-time applications such as those found in ICU and mobile settings. Another problem is that XML cannot necessarily be viewed everywhere. It needs a processing application. XML browsers are not prevalent, so the document must be translated into HTML before publication. If it is not changed into HTML, programmers must code a processing application.


Widespread XML use is still off in the distance, but it is a growing presence in the medical device and healthcare industries. As regulations for medical device companies and hospitals grow more stringent, data transfer languages such as XML become more important.

The key to its ultimate acceptance is its system flexibility, which means it will be of service to future technologies. In the years to come, wireless devices of every stripe will be able to communicate using XML. The advantage is not that it changes the systems it works with, but that it adapts to the available technology.

Brendan Gill is an associate editor of MD&DI.

Copyright ©2005 Medical Device & Diagnostic Industry

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