Laboratories are typically divided into sections or departments by scientific disciplines. In large laboratories high-volume testing from two or more disciplines may be gathered together into an ‘automated testing’ department. The major disciplines within pathology are:

1. Clinical chemistry – the measurement of chemical substances such metabolic products, proteins and drugs in blood and sometimes other specimens.

2. Haematology – the analysis of the various cell types in blood, the measurement of blood clotting or coagulation, the assessment of bone marrow specimens and blood banking.

3. Microbiology and Serology – the evaluation of infectious diseases. This involves detection of microorganisms by microscopy, growing (culturing) infectious organisms from a variety of specimens, identification of specific organisms and measurement of their susceptibility to antibiotics, detection of specific bacteria, viruses, fungi and parasites by specialised assays and measurement of antibodies in blood produced in response to infections or immunisations.

4. Immunology – the assessment of the antibody and cellular components of the immune system. A large part of immunological testing is directed toward evaluating the many autoimmune diseases to which we are susceptible. In these diseases the immune system turns inwards to damage a variety of tissues and organs within the body.

5. Molecular pathology and Cytogenetics – this is a rapidly growing area which uses DNA technology and chromosome manipulation techniques to evaluate inherited and acquired problems in genes and chromosomes.

6. Cytology – the microscopic assessment of individual or groups of cells that are either shed in body fluids or collected by smears and scrapings (e.g. the Pap smear), or by aspiration from deeper tissues through a very fine needle.

7. Histopathology – the microscopic study of tissue specimens obtained from the body by surgical removal or by needle biopsy of a solid core of tissue. Histopathologists also perform autopsies in hospitals.