Knowledge-based interpretation of serologic tests for hepatitis on the World Wide Web

HEPAXPERT is a knowledge-based system that interprets the results of routine serologic tests for infection with hepatitis A and B viruses. The following tests are included: hepatitis A virus antibodies, IgM antibodies to the hepatitis A virus, hepatitis A virus in stool, hepatitis B surface antigen and antibodies, antibodies to hepatitis B core antigen, and hepatitis B envelope antigen and antibodies. HEPAXPERT/WWW, an implementation of HEPAXPERT-III for the World Wide Web, can be reached by URL http://www.med-expert.co.at/hepax. After selecting HEPAXPERT/WWW, serologic test results can be entered and will be transferred as an E-mail message for subsequent interpretation, which is done off-line with HEPAXPERT-III. The textual interpretation is sent back via E-mail. Each qualitative test for hepatitis A and B antibodies and antigens may produce one of four possible results: positive, negative, borderline, and not tested. To cover the resulting 64 (A) and 57,344 (B) combinations of findings, the knowledge base of HEPAXPERT/WWW contains 16 rules of hepatitis A and 131 rules for hepatitis B serology interpretation. This basic knowledge is structured such that all possible combinations of findings can be interpreted, and there is no overlap in the premises underlying the rules. The reports that the system automatically generates include the transferred results of the tests; a detailed analysis of the results, including virus exposure, immunity, stage of illness, prognosis, infectiousness, and vaccination recommendation; and, as an option, an identification, to distinguish the origin of the interpretation requests.