The word "pathology" means the study of diseases processes. Pathology involves examining the cause of illness, how it develops, the effect of the illness on cells and the outcome of the illness.

The aspects of illness that may be studied include cellular pathology, cell necrosis or cell death, wound healing, cancer formation and inflammation. A combination of both anatomical pathology and clinical pathology is termed general pathology.

For a person to qualify as a pathologist, they need to complete a medical degree and a residency program that leads to certification from approved boards.

Branches of pathology

Some important branches and sub-branches of pathology include:

Anatomical pathology

This area of pathology involves the examination of surgical specimens removed from the body or sometimes the examination of the whole body (autopsy) to investigate and daignose disease. On examining a biopsy, the following aspects are considered:

• Gross anatomical make up of the sample
• Microscopic appearance of cells
• Chemical signatures in the sample
• Immunological markers present in the cells
• Molecular biology of the cells, organs, tissues and sometimes whole body

Anatomical pathology is further classified into sub specialities, examples of which include:

• Surgical pathology - This involves the examination of specimens obtained during surgery such as a breast lump biopsy obtained during mastectomy
• Histopathology - This refers to the examination of cells under a microscope after they have been stained with appropriate dyes.
• Cytopathology - In cytopathology, cells that have been shed into bodily fluids or have been obtained by scraping or aspirating tissue are examined. Typical examples include cervical smear, sputum and gastric washings.
• Forensic pathology involves the post mortem examination of a corpse for cause of death using a process called autopsy.
• Dermatopathology concerns the study of skin diseases.

Clinical pathology

This branch of pathology involves the laboratory analysis of body fluids (such as blood, urine or cerebrospinal fluid) and bodily tissue for the diagnosis of disease. Some of the main subspecialities of clinical pathology include:

• Chemical pathology, also called clinical chemistry, involves the assessment of various components in bodily fluids such as the blood or urine, although for the main part it concerns the analysis of blood serum and plasma.
• Immunology or immunopathology refers to the study of immune system disorders such as immunodeficiencies, organ-transplant rejection and allergies.
• Hematology or hematopathology concerns the investigation and diagnosis of blood diseases.

Molecular pathology

Molecular pathology is a multi-disciplinary field that focuses on disease at the sub microscopic, molecular level. Aspects studied may include a mixture of anatomical pathology, clinical pathology, genetics, molecular biology and biochemistry.