Around 1989, Steven Schueler started working on a computer program that could perform symptom triage. The intent was to create something that patients could use to safely decide what to do when they were sick. In 1990, his company DSHI Systems released “Home Medical Advisor” on a floppy disk. Later it was issued on CD-ROM’s, and claims to have sold over 2 million copies over the years. A major win for DSHI since 1999 has been its adoption by the Veterans Health Administration (VHA) as the Veterans Health Gateway (VHG). VHG provides over 300 symptom/condition-based triage algorithms and related patient education information and is used by VHA nurses to provide health advice via the telephone.
FreeMD is the free online version of the same underlying triage application. It uses video to conduct the interview, ask questions and then generates a custom web page that contains care instructions and suggested next steps. I tested it with a few hypothetical cases (from benign nose bleed to serious UTI) and it seemed to do fine for basic diagnosis. With vague complaints like diffuse abdominal pain and vomiting, it stayed roughly in the right categories at a high-level (appendicitis, pancreatitis, kidney stones, gallbladder disease, intestinal obstruction).
Is the underlying logic based on hierarchical structured programming or a more sophisticated expert system with forward and backward chaining algorithms? I don’t know. My interest in FreeMD spiked when I saw the 100K+ unique visitors/month statistic. They are consistently generating a lot of traffic, so there’s got to be fairly comprehensive content and at least some utility in the service. My personal impression is that as a patient-oriented triage tool, it does well. Of course, provider-oriented decision support is tougher and I don’t expect it to hold up like Mcyin or DXplain.
I’m also intrigued why DSHI systems chose to make their application available for free, when the revenue model seems to be based on licensing/co-branding with partners. I was half-expecting to see a feedback loop on FreeMD (like “Was this the right diagnosis? Let us know”) since one of the major reasons for open-sourcing anything is to leverage wisdom of crowds. But there isn’t anything like that, so maybe its all about gaining awareness and marketing the application.
Update: Connected with Dr. Steven Schueler after writing this post. He correctly identified that FreeMD is a triage system, so its a bit unfair to compare it with diagnostic decision support systems like Mycin/DXplain.

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Here is a half-baked idea that adds another data point to my rant about how keeping a record of health-related activities is useful, and how web 2.0 technologies can help enable such a record. 
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