DXplain can be used as an electronic medical textbook, a medical reference system and as a diagnostic clinical decision support tool.

As a decision support system, DXplain "uses a set of clinical findings (signs, symptoms, laboratory data) to produce a ranked list of diagnoses which might explain (or be associated with) the clinical manifestations. DXplain provides justification for why each of these diseases might be considered, suggests what further clinical information would be useful to collect for each disease, and lists what clinical manifestations, if any, would be unusual or atypical for each of the specific diseases. "

Access to the full, interactive DXplain requires a license from Massachusetts General Hospital and is limited to hospitals, medical organizations and medical schools.