When a doctor orders a series of tests on a patient, chances are that those tests will be performed by medical and clinical laboratory technologists. It is the job of these professionals to examine and analyze blood, urine, and other body fluids, tissue, and cells. Using powerful microscopes and other equipment, they look for bacteria, parasites, and abnormal cells. They also analyze blood cholesterol levels and type and cross-match blood samples for transfusions. In larger labs, like those at many hospitals, technologists tend to specialize in blood work, microbiology, or some other area. Supervising medical and clinical technicians may also be part of the job. The work can be stressful, as when you must perform a complex test perfectly in a limited amount of time. But is also satisfying to know that you are providing the vital information a doctor needs to save a life or to cure a disease.