Knowledge representation and compilation for symptom-disease-test relationships

A method that represents and compiles expert knowledge for choosing diagnostic tests is presented. This knowledge is categorized into three relations. The relation SD is defined on the domains symptom/sign and disease, the relation DT is defined on disease and diagnostic test, and the relation DD is defined on disease and disease where the first attribute (column) in each relation, respectively, is a primary key (that is, there exists precisely one value) and the second is a set of values. The authors show that redundant tuples can be reduced or decomposed by checking whether or not there exist tuples whose set of diagnostic tests is equivalent to that of other tuples or are a subset of others. Finally, they can obtain a preferable set of diagnostic tests for given symptoms/signs by using the combination of SD and DT; for further diagnosis, the combination of DD and DT is applicable.