Pathology (from Greek πάθος, pathos, "fate, harm"; and -λογία, -logia) is the study and diagnosis of disease through examination of organs, tissues, bodily fluids and whole bodies.

Pathology can be theoretical (general pathology) or applied to the diagnosis of disease (medical pathology). Medical pathology is further divided in two main branches, Anatomical pathology and Clinical pathology.

In practice, all physicians diagnose diseases. Pathology, however, is unique in that pathologists typically do not see patients directly, but rather serve as consultants to other physicians. Pathology is therefore best defined as laboratory medicine.

Veterinary pathology is concerned with animal disease whereas Phytopathology is the study of plant diseases.

History of pathology

The history of pathology can be traced to the earliest application of the scientific method to the field of medicine. The first physician known to have made postmortem dissections was the Arabian physician Avenzoar (1091–1161). Rudolf Virchow (1821–1902) is generally recognized to be the father of microscopic pathology.

General pathology

General pathology, also called investigative pathology, experimental pathology or theoretical pathology, is a broad and complex scientific field which seeks to understand the mechanisms of injury to cells and tissues, as well as the body's means of responding to and repairing injury. Areas of study include cellular adaptation to injury, necrosis, inflammation, wound healing and neoplasia.

The term "general pathology" is also used to describe the practice of both anatomical and clinical pathology.

Pathology as a medical specialty

Pathologists are physicians who diagnose and characterize disease in living patients by examining biopsies or bodily fluid. The vast majority of cancer diagnoses are made or confirmed by a pathologist. Pathologists may also conduct autopsies to investigate causes of death. Pathologists manage the medical laboratories. Pathology is a core discipline of medical school and many pathologists are also teachers.

To be licensed, candidates must complete medical school (four years), an approved residency program (five years) and successfully write a certification examination by an appropriate body. In the US, certification is by the American Board of Pathology.

Medical pathology is divided into two main specialties, anatomic pathology and clinical pathology.

Anatomic Pathology

Anatomic pathology is a medical specialty that is concerned with the diagnosis of disease based on the gross, microscopic, and molecular examination of organs, tissues, and whole bodies (autopsy).

Anatomical pathology is itself divided in subspecialties. The following sub-specialties are recognized by the American Board of Pathology :

• surgical pathology
  • dermatopathology
  • neuropathology
  • pediatric pathology
• cytopathology
• forensic pathology
• molecular genetic pathology.

Clinical Pathology

Clinical pathology, also called Laboratory Medicine, Biopathology or Clinical/Medical Biology, is a medical specialty that is concerned with the diagnosis of disease based on the analysis of bodily fluids such as blood and urine.

Clinical pathology is itself divided in subspecialties. The following sub-specialties are recognized by the American Board of Pathology :

• chemical pathology (clinical chemistry)
• hematology
• blood banking and transfusion medicine
• Medical microbiology pathology

Forensic Pathology

Forensic pathology is a branch of Pathology concerned with determining the cause of death by examination of a cadaver. The autopsy requested by a coroner usually during the investigation of suspicious deaths. Forensic pathologists are also frequently asked to confirm the identity of a cadaver.