Introduction to Pathology

Laboratory Autopsy
An Introduction to Pathology

Pathology is the study and diagnosis of disease through examination of organs, tissues, bodily fluids, and whole bodies (autopsies).   The history of pathology can be traced to the earliest application of the scientific method to the field of medicine, a development which occurred in the Middle East during the Islamic Golden Age and in Western Europe during the Italian Renaissance.

Early systematic human infections were carried out by the Ancient Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC.   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. Most early pathologists were also practicing physicians or surgeons.

General Pathology

General 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.   It forms the foundation of pathology, the application of this knowledge to diagnose diseases in humans and animals.

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

Anatomic Pathology

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

Anatomic pathology is itself divided in subspecialties, the main ones being surgical pathology, cytopathology and forensic pathology. To be licensed to practice pathology, one has to complete medical school and secure a license to practice medicine. An approved residency program and certification (in the U.S., the American board of Pathology or the American Osteopathic Board of Pathology) is usually required to obtain employment or hospital privileges.

Anatomic pathology is one of two branches of pathology, the other being clinical pathology, the diagnosis of disease through the laboratory analysis of bodily fluids and/or tissues. Often, pathologists practice both anatomic and clinical pathology, a combination known as general pathology. The distinction between anatomic and clinical pathology is increasingly blurred by the introduction of technologies that require new expertise and the need to provide patients and referring physicians with integrated diagnostic reports. Similar specialties exist in veterinary pathology.

Clinical Pathology

Clinical pathology or Laboratory medicine, is a medical specialty that is concerned with the diagnosis of disease based on the laboratory analysis of bodily fluids such as blood and urine, and tissues using the tools of chemistry, microbiology, hematology and molecular pathology. Clinical pathologists work in close collaboration with medical technologists, hospital administrations, and referring physicians to ensure the accuracy and optimal utilization of laboratory testing.

Clinical pathology is one of the two major divisions of pathology, the other being anatomic pathology. Often, pathologists practice both anatomic and clinical pathology, a combination sometimes known as general pathology.

Forensic Pathology

Forensic pathology is a branch of pathology concerned with determining the cause of death by examination of a cadaver. The autopsy is performed by the pathologist at the request of a coroner usually during the investigation of criminal law cases and civil law cases in some jurisdictions. Forensic pathologists are also frequently asked to confirm the identity of a cadaver.

Veterinary Pathology

Veterinary pathologists are doctors of veterinary medicine who specialize in the diagnosis of diseases through the examination of animal tissue and body fluids. Like for medical pathology, veterinary pathology is divided in two branches, anatomical pathology and clinical pathology. Veterinary pathologists are critical participants in the drug development process.

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.  Pathology is a core discipline of medical school and many pathologists are also teachers. As managers of medical laboratories, pathologists play an important role in the development of Laboratory information systems. Although the medical practice of pathology grew out of the tradition of investigative pathology, most modern pathologists do not perform original research.

Pathology is a unique medical specialty in that pathologists typically do not see patients directly, but rather serve as consultants to other physicians (often referred to as "clinicians" within the pathology community). To be licensed, candidates must complete medical training, an approved residency program and be certified by an appropriate body. In the US, certification is by the American Board of Pathology or the American Osteopathic Board of Pathology.