What specialty does House’s department represent in House M.D.?

House’s department in House M.D. represents diagnostic medicine.

The Department of Diagnostic Medicine handles patients whose illnesses remain unexplained after routine tests and consultations. House and his fellows combine medical history, laboratory results, imaging, and sometimes ethically controversial investigations to identify the underlying disease.

Diagnostic medicine is distinct from a single organ-based specialty such as cardiology or neurology. Real-world diagnostic practice can involve internal medicine, laboratory medicine, pathology, radiology, and multidisciplinary consultation. The show dramatizes that process by concentrating unusual cases into a small specialist team.

House is also described as having expertise in infectious disease and nephrology, but those are not the name of his hospital department. This distinction causes a frequent mix-up: the question concerns the organizational unit he heads, not every medical field in which he is trained or knowledgeable.