What specialty does Dr. Gregory House lead in House M.D.?

Dr. Gregory House leads the Department of Diagnostic Medicine in House M.D.

The department handles unusually difficult cases that have resisted more conventional diagnoses. House and his team investigate symptoms, review medical histories, order tests, and revise hypotheses as new evidence appears. This structure gives the series its recurring medical-detective format.

House is also described as an infectious-disease specialist and nephrologist, but those are his medical specialties rather than the name of the hospital department he heads. Emergency medicine, neurology, and surgery appear in many episodes, yet none is House's department. Diagnostic medicine is the precise answer because it identifies his departmental role.