Gregory House is board-certified in nephrology alongside infectious disease.
Nephrology is the medical specialty focused on the kidneys and their diseases. Infectious disease concerns illnesses caused by pathogens and the treatment of complex infections. House's combination of specialties helps explain why he is particularly valuable when a case involves unexplained organ failure, systemic illness, or unusual infection.
The series generally presents House as a diagnostician rather than as a physician who performs routine specialty practice. His team draws on many disciplines, but House's own credentials are repeatedly associated with nephrology and infectious disease.
Nephrology should not be confused with urology. Nephrologists treat medical kidney disorders, while urologists manage the urinary tract and perform many related surgical procedures. That distinction makes nephrology the precise answer when the question asks for House's board certification.