The correct word to fill in the blank is "Blood Bank" department. The Blood Bank department is responsible for performing blood typing and compatibility testing of patients’ blood with blood products for transfusion purposes. They are also responsible for collecting, processing, and storing blood donations, and ensuring the safety and quality of blood products used in transfusions. The Blood Bank department plays a critical role in the healthcare system by ensuring that patients receive safe and compatible blood products when they need transfusions.