Messages vs. Documents

I have wanted to write about this topic for a while. Keep in mind that I am a clinician and not an engineer so what follows is my interpretation of how systems work.

The standards used to collect and manage the data most important to clinicians seem to come in two flavors, either messaging or documents. The newer standards and profiles that are being developed that deal with clinical workflow issues, clinical decision support, and reporting (quality and public health, for example) will not be the primary focus here. They are important to keep in mind however because of they will grow in significance over the next few years. The transition from Stage 1 through Stage 3 of Meaningful Use will drive future developments.

Documents have traditionally formed the bulk of the medical records clinicians keep on their patients. They provide a sense of permanence; they are not something to be used once and then discarded. Examples are history and physicals, discharge summaries, consultations, procedure reports, consents, and even laboratory reports. Documents, in the paper world, are so useful that their incorporation into electronic medical records should come as no surprise.

ASTM developed CCR, a sentinel standard for a clinical summary document. HL7, in an example of parallel innovation, developed CCD. Both are in common use today in EMRs. Superficially they seem very similar-section headers are similar and both are based on the XML programming language that offers the advantages of being both human readable and machine computable. At the core level though, they are different. CCR is strictly defined and modifications are therefore difficult. CCD, on the other hand is just one incidence of use of a standard developed by HL7, CDA or clinical document architecture. In simple terms, CDA is like an envelope and the letter it contains. On the outside there is certain routing information (like postage, address, and return address) and on the inside is the actual letter itself. There are potentially endless possibilities for CDA documents. HL7, IHE, and HITSP (when it still existed) have been leaders in development and amplification of this standard with implementation specifications/profiles. There are plans to develop a CDA template library/repository (see recent blog article by Keith Boone.) If vendors incorporate these templates into their systems, it will be a major step forward for interoperability. John Halamka recently wrote a blog article about how clinical summaries are used at his institution.

Vendors have voluntarily subjected their systems to interoperability testing at the annual IHE Connectathon, Many have then demonstrated their achievements at the HIMSS Interoperability Showcase that is featured at the HIMSS annual convention and trade show. One of the requirements for Stage 1 of Meaningful use is the ability of the EMR to create CCR or CCD documents. NIST (the National Institute for Standards and Technology) has developed tools that will be used to validate recognized CDA documents. These tools will be used by the yet to be determined certification agencies and testing labs during the required certification testing of EMRs.

Messaging standards are used for EMR tasks that tend to be more transient and process oriented. HL7 has developed complex standards for laboratory orders and lab results. X12 has developed standards to handle many of the administrative processes utilized in medical insurance related transactions such as eligibility checking, verification of insurance, claims processing, and prior authorization. There are a number of standards used to coordinate scheduling tasks.

I will reveal my bias and say that many of these purposes could be readily served by a document centric rather than a message-centered approach. For example, I would like to have a prior authorization document in my chart before I proceed with surgical care of a patient. Also, lab orders have traditionally been initiated by a document in the inpatient chart. Similarly, although lab results can be useful in message form, a lab result document is usually what clinicians use when they treat patients. HITSP recognized this dichotomy and worked last summer to harmonize standards for both lab result messages and lab result documents.

In the future, clinical decision support systems are likely to play an increasingly important role the EMR. Likewise, EMRs will be required to have the ability to collect and process data to provide a wide variety of quality reports and to forward data to public health entities. It would be idea if the clinical data to drive the necessary systems were collected at the point of care as a seamless function of providing care. Primarily, documents will be the source of the data that will facilitate this goal. The challenge will be to map the data elements so they can be easily accessed to be processed to complete the new tasks being developed.