What Is a Pathologist?

Medical pathologists, also known simply as pathologists, are physicians who are trained to investigate the cause and effect of diseases or injuries. They do so mainly through the analysis of organ, tissue, blood, or body fluid samples.

Medical pathologists are broadly classified as either anatomical or clinical pathologists. Anatomical pathologists perform visual, microscopic, and molecular analyses of tissues, organs, and whole bodies (such as during an autopsy). Clinical pathologists diagnose disease based mainly on the lab analyses of blood, urine, and other body fluids.

Pathologists require extensive education and training, comprised of four years of college, four years of medical school, and three to four years in a pathology residency program. The majority of pathologists will pursue additional training with a one- to two-year fellowship in a pathology subspecialty.

Concentrations

Medical pathology is not constrained to a single disease, population, or organ system. It is a field of medicine whose practitioners identify the cause and effect of illness so that patients can be accurately and effectively treated.

Pathologists are often considered a "doctor's doctor" because they assist doctors in making diagnoses and the appropriate treatment decisions. Although anatomical and clinical pathologists work in similar environments and have similar diagnostic goals, there are key differences in the professions.

Anatomical pathologists center their investigations on tissues and organs. Historically, the practice was largely devoted to post-mortem investigations but today includes a variety of procedures to diagnose diseases, like cancer, based on the analyses of surgical specimens.

Clinical pathologists diagnose disease based on the analysis of body fluids or cells obtained from tissue extracts. Clinical pathology is the specialty whose tests are more familiar to the general public, such as a complete blood count, urinalysis, blood glucose test, and throat culture.

Procedural Expertise

Because their roles and functions are so distinctive, anatomical and clinical pathologist will rely on different tools and techniques. Although there will be some overlap in procedures (particularly molecular and genetic testing), many of the tools used are specific to specimens being analyzed.

Anatomical Pathology

When provided an organ or tissue sample, anatomical pathologists will usually proceed from a visual to a microscopic to a molecular analysis. Common procedures include:

• Gross examination, the examination of diseased tissue with the naked eye, a magnifying glass, or a standard light microscope
• Cytopathology, the examination of tissues at the cellular level, including tissues and cells obtained through a surgical biopsy or fine needle aspiration (FNA)
• Histopathology, the microscopic examination of specially stained tissues to identify normal and abnormal structures in a cell and/or tissue structure
• Electron microscopy, a type of microscope that uses accelerated electrons to increase magnification, enabling the visualization of the structures inside of a cell
• Immunohistochemistry, the use of immune proteins (called antibodies) that, when matched to receptors on cells (called antigens), can aid in the identification of cancer and certain viral infection
• Fluorescence in situ hybridization (FISH), a molecular technique similar in principle to immunohistochemistry in which RNA or DNA is matched to corresponding DNA or RNA in a specimen to identify specific cancers or chromosomal abnormalities
• Tissue cytogenics, a range of molecular techniques that identify chromosomal disorders by pinpointing errors in their genetic sequence
• Flow immunophenotyping, a technique especially useful in leukemia or lymphoma in which a tissue sample is exposed to different antibodies to identify normal and abnormal cell types

Clinical Pathology

When provided blood, urine, or other body fluids, a clinical pathologist will usually proceed from a visual to a microscopic to a lab analyses. Unlike anatomical pathologists, clinical pathologists will run tests based on a physician's suspicion and return results that either support or exclude that suspicion. The procedures can be broadly described as:

• Macroscopic examinations, a visual evaluation of a sample to check for abnormalities, such as color, density, coagulation, and sedimentation
• Microscopic evaluations, using various techniques and stains (such as bacterial gram staining and FISH) to examine a specimen microscopically
• Automated analyzers (a.k.a. "lab tests"), a wide range of calibrated equipment used to evaluate specimens and determine whether they fall above, below, or within the expected values (reference range) of the general population
• Lab cultures, in which a specimen is applied to a culture medium with the aim of growing and positively identifying bacterial, fungal, and even viral pathogens (disease-causing agents)

Subspecialties

Because the clinical applications of pathology are so vast, it is not uncommon for pathologists to seek further training to specialize in a specific field of practice.

Among the subspecialties anatomical pathologists commonly pursue:

• Cytopathology, the study of disease on a molecular level
• Forensic pathology, involving the determination of the cause of death, both natural and unnatural
• Neuropathology, the identification of disease from brain and nerve tissues
• Pediatric pathology
• Surgical pathology, involving the gross and microscopic examination of surgical specimens

Among the subspecialties clinical pathologists commonly pursue:

• Blood banking and transfusion medicine
• Chemical pathology, involving the use of lab tests to diagnose and monitor disease
• Clinical microbiology, focused specifically on infectious diseases
• Cytogenetics, the study of the inheritance of chromosomal disorders
• Hematopathology, focused on the evaluation of blood

Many of these specialists will go on to become medical examiners and coroners or to work in genetics labs and medical research facilities.

Training and Certification

To become a pathologist, you must first get a bachelor's degree from an accredited college. You do not need to pursue in any specific major but must complete the required pre-medical courses, including biology, physics, English, and social sciences. You would also need to take the Medical Competency Aptitude Test (MCAT) a year before graduating, which most medical schools use to select students.

The first two years of medical school are devoted primarily to classroom studies. The second two years is comprised of clinical rotations in hospitals and medical facilities to gain broad exposure to the different fields of medicine. Upon graduating, you would be awarded a degree as either a doctor of medicine (MD) or a doctor of osteopathic medicine (DO), depending on the medical school you were enrolled in.

To begin practicing, you would need to get a medical license in your state. Licensing requirements vary, but most states require you to pass a national exam and, in some states, an additional state exam.

Upon attainment of your license, you would next begin a three-year residency program in either anatomical or clinical pathology. There are around 145 accredited programs nationwide. You can also opt to train in a combined four-year program in anatomical and clinical pathology (AP/CP).

Upon the completion of residency, most pathologists will obtain board certification from the American Board of Pathology (ABP) by passing a written and practical exam. Those who do tend to have more job opportunities.

ABP certification must be renewed every 10 years, during which time you must maintain a certain number of study hours by participating in accredited continuing medical education (CME) programs.

A Word From Verywell

If you are considering a career in pathology, the job prospects appear excellent given the ongoing shortage of practitioners in all fields of practice. According to a 2018 study in Academic Pathology, there will likely be an acute gap in filling positions by 2030 as more and more senior pathologists reach retirement age.

Pathology is generally less stressful than other medical professions since you don't see patients and work relatively normal office hours. As such, the job can afford a pathologist a better work-life balance along with respectable remuneration.