Lab technicians play an essential role in the study and treatment of diseases. They are responsible for assisting physicians in hospitals and doctor’s offices by collecting samples and performing tests on tissues, blood, and other body fluids. The tests they perform and the results they gather help doctors diagnose patients and determine causes of illnesses. Lab technicians may work in all general areas of a laboratory or doctor’s office, or they may choose to specialize. For example, immunohematology technologists collect and prepare blood donated for transfusions, while immunology technologists examine the human immune system.