The Pathology Institute

The Pathology Institute (TPI) was a prominent provider of anatomic pathology and clinical laboratory services based in Southern California. The company specialized in delivering high-quality diagnostic insights through surgical pathology, cytopathology, and immunohistochemistry to a broad network of hospitals, clinics, and physician practices. Known for its diagnostic accuracy and subspecialty expertise, TPI played a critical role in clinical decision-making for oncology and other complex disease areas. In 2004, the company was acquired by Quest Diagnostics, a move that significantly expanded Quest's regional pathology footprint and integrated TPI's specialized services into a national diagnostic network.