Medical and clinical laboratory technologists 

They generally have a bachelor's degree in medical technology or in one of the life sciences, or they have a combination of formal training and work experience. They perform complex chemical, biological, hematological, immunologic, microscopic, and bacteriological tests. Technologists microscopically examine blood, tissue, and other body substances. They make cultures of body fluid and tissue samples, to determine the presence of bacteria, fungi, parasites, or other microorganisms.

Medical and clinical laboratory technologists evaluate test results, develop and modify procedures, and establish and monitor programs, to ensure the accuracy of tests. Some medical and clinical laboratory technologists supervise medical and clinical laboratory technicians. They analyze samples for chemical content or reaction and determine blood glucose and cholesterol levels. They also type and cross match blood samples for transfusions.

Technologists in small laboratories perform many types of tests, whereas those in large laboratories generally specialize. Technologists who prepare specimens and analyze the chemical and hormonal contents of body fluids are clinical chemistry technologists. Those who examine and identify bacteria and other microorganisms are microbiology technologists. 

Blood bank technologists, orimmunohematology technologists, collect, type, and prepare blood and its components for transfusions. Immunology technologists examine elements and responses of the human immune system to foreign bodies. Cytotechnologists prepare slides of body cells and microscopically examine these cells for abnormalities that may signal the beginning of a cancerous growth. Molecular biology technologists perform complex genetic testing on cell samples.