A pathologist is a doctor who looks at bodies and body tissues. They run tests in a lab and often work in tandem with other medical specialists to diagnose medical conditions. Pathology is broken up into numerous specialties.

Pathology is the study of diseases, their causes, their progression, and their effect on the human body. The name comes from the Greek word “pathología,” which means “suffering.”

In the context of pathology, “disease” is any deviation from a set of observable characteristics of an individual resulting from the interaction of their genes with their environment. This deviation is quantified and measured via symptoms reported by the person experiencing them, as well as signs measured through tests by a pathologist.

The cause of the disease is referred to as its etiology. Disease develops through a series of chemical or cellular reactions, which a pathologist studies and investigates.

Learn more about the role of a pathologist below.

A pathologist analyzes tissues, cells, and bodily fluids. They are an important part of a medical professional team, often tasked with answering important questions about disease, such as:

  • “What is it?” (a diagnosis)
  • “How is it going to behave?” (a prognosis)
  • “How should it be treated?” (treatment strategy)

Pathologists make this determination by looking at the cellular, chemical, and mechanical behavior of body and its tissues, using their observations, the results of tests they perform, and newly developed computing technologies.

These medical doctors specialize in looking at human tissue, blood, urine, and other bodily fluids under a microscope. Oftentimes, they work in the background without speaking to patients.

According to a paper published in 2020, the role of pathologists in medical research and treatment is growing as the human genome is deciphered, and as complex interactions of cellular biochemistry are refined and the risk of disease is more accurately calculated.

There are several sub-specialties of pathology, and these medical specialists usually focus on one to several types.

  • Blood banking and transfusion: This type of pathologist maintains an adequate blood supply, blood donor and recipient safety, and appropriate blood use at a medical facility. They direct the preparation and safe use of specially prepared blood components, including red blood cells, white blood cells, platelets and plasma constituents, and bone marrow or stem cells for transplantation.
  • Clinical pathology: A clinical, or chemical, pathologist specializes in the biochemistry of the human body to understand disease diagnosis and progression. They monitor substances in bodily fluids like blood and urine to assess changes in someone’s body.
  • Clinical informatics: These specialists evaluate data, health trends, and communication systems and use this information to improve medical processes that will allow for better patient outcomes. Think of them as the quality control of pathology.
  • Cytopathology: This type of pathology is the study of individual cells of the body. The human body is made up of millions of cells that can be looked at under the microscope to help diagnose medical conditions. It’s often used to diagnose cancer, other conditions of the respiratory, urinary, and gastrointestinal tracts, and thyroid gland, salivary glands, and lymph nodes.
  • Dermatopathology: This discipline specializes in human skin diseases. It involves the microscopic examination, description, and interpretation of biopsy specimens. Dermatopathologists often have training in dermatology.
  • Forensic pathology: This is the study of tissue or bodily fluid in a person after their violent, sudden, and unexpected death. Forensic pathologists are sometimes also medical examiners or coroners, performing autopsies for a government law enforcement agency. Their job is to identify the cause and manner in which someone died.
  • Hematopathology: A hematologist studies conditions specific to blood cells, blood clotting, bone marrow, and lymph nodes. They use blood samples to diagnose conditions like anemia and blood cancers.
  • Medical microbiology: This discipline specializes in infectious organisms and diseases. They take part in the work to prevent, diagnose, and treat conditions that result from microorganisms.
  • Molecular genetic pathology: This type of specialist expert investigates gene structure, function, and mutations. They use laboratory testing to help diagnose, treat, and provide a prognosis for people with genetic disorders, infectious diseases, and human development. They also help determine the risk of genetic disorders.
  • Neuropathology: Neuropathologists study conditions that affect the nervous system and skeletal muscles. They often work with neurologists and neurosurgeons to diagnose neurological diseases, and also analyze tissue samples following death to study dementia, assess trauma, and evaluate genetic conditions.
  • Surgical pathology: This is the study of the tissues removed during surgery—such as a tumor—to help diagnose a disease and determine a treatment plan. This can sometimes occur while a surgery is ongoing, and can inform surgeons on how to proceed.
  • Pediatric pathology: This type of pathology involves the research of conditions that occur during fetal growth, infancy, and child development. Pediatric pathologists investigate diseases in children up to 18 years of age.

In order to become a pathologist in the United States, a medical professional starts with a four-year undergraduate degree, often in chemistry or biology. Next is a four-year doctorate degree in medicine, either for a doctor of medicine (MD) or doctor of osteopathic medicine (DO).

This is followed by a medical residence in a medical facility, which for pathology usually lasts for three years. Combined residencies in both anatomical and clinical pathology can take four years or longer.

Doctors who want to specialize in a particular type of pathology must then complete additional training before being certified by the American Board of Pathology.

In all, the process can take 11 years or longer.

Pathologists are medical doctors who study the cause and progression of a disease or injury by looking at body tissues and fluids. They often have expertise in specific subspecialties and frequently help other physicians with the diagnosis, prognosis, and treatment of conditions.