Involves testing on clinical specimens for information about the health of a patient, for the diagnosis, treatment, and prevention of disease. Disciplines include chemistry, blood banking, hematology, microbiology, immunology, cytology, histology, pathology and cytogenetics. May include highly technical sub- specialty areas such as enzyme assay, steroid assay, radioimmunoassay, toxicology, electrophoresis, rheumatology, tissue typing, and virology.