xHTML, Microformats, SNOMED-CT and Medical Records
February 29th, 2008 andrewWe know we want good semantics in messages and the best way to get that is atomic data in a standards based format. However the roadblock we run up against is that its not sexy enough!
The availability of computers rather than typewriters for Medical Notes means that the visual presentation of a clinic report or letter has become important to many and when you suggest that readers are really interested in the content rather than the presentation you often get that sinking feeling that you have just lost them.
So it seems to keep everyone happy we need both. However that sexy display needs to be portable and ideally standards based. It is also desirable to have some semantics in the display so a consumer of the report can eg. Click on a drug or diagnosis to drill down for more information. Ideally combining the atomic data in the HL7, which for example include images, with a standards based display format using xHTML and CSS, would fit the bill. Using Microformats it would also be possible to mark up diagnoses and drugs with there SNOMED-CT representation.
eg. Say you wanted to say the patient Had “Large B-Cell Lymphoma” – as Text this is not something you can reliably parse out, however if you used Microformats in xHTML you could represent it as:
<span title=”64572001|Disease| : 116676008 = 46732000|Malignant Lymphoma, large B-cell diffuse|”>Large B-Cell Lymphoma</span>
Or for usual more compact usage you could just use the SNOMED-CT codes alone:
<span title=”64572001 : 116676008 = 46732000″>Large B-Cell Lymphoma</span>
Now this embedded in the display text has real meaning and could be used as a link for disease information for example. The Australian HL7 V2 standard defines a html display segment, as the last OBX in a message and by transmitting the atomic data in the preceding OBX segments for machine usage and including a xHTML display segment you get the best of both worlds, atomic data and sexy display. If you add microformats to the xHTML then the display still has semantics that are safely extracted. The SNOMED-CT grammar can also go further and define such information as “This is a past history or Family History of a disease” which extends the semantics further.
Currently HL7 Freetext is used for display, and the only real formatting available is bold. This is causing some user pushback and a move to xhtml and CSS (probably with no javascript and inline CSS) would allow the embedding of good display into messages containing atomic data. HL7 CDA – Clinical Document Architecture allows to a html display segment as well so the concept is usable here as well. The alternatives would be rtf display, but xhtml is far more semantic and standard and is likely to be more inter-operable. There are free xhtml validators on the web and some form of view control is installed in virtually every OS available, which increases the attractiveness of xhtml.
It is an idea we are exploring at this time.