Department of Pathology and Department of Microbiology at Queen Mary Hospital constitute the Hospital Pathology Services (HPS) that serves the Hong Kong West Cluster. Its service also extends to other health care institutions in both the public and private sectors territory-wide at the tertiary level. HPS works closely with its counterparts from the LKS School of Medicine of The University of Hong Kong (HKU) in service delivery and training for medical students, pathologists, laboratory scientists and technicians. The whole organization of HPS has been accredited by the College of American Pathologists since 2002, attesting to its internationally recognized standard and quality of service.

Department of Pathology (the Department) at Queen Mary Hospital comprises 5 divisions, namely Anatomical Pathology, Chemical Pathology, Haematology & Blood Bank, Clinical Immunology as well as Transplantation & Immunogenetics.