Sampling of abdominal fluid can be done to aid the diagnosis of free abdominal fluid, which is an abnormal finding in dogs and cats. This is typically done with ultrasound guidance if the patient has a very small amount of free fluid. Therapeutic abdominocentesis can also be performed, which is the removal of large quantities of free abdominal fluid. Abdominal fluid can be caused by bleeding in the abdominal cavity (e.g. splenic cancer), severe inflammation of abdominal organs, infection in the abdominal cavity (perforated intestines, gallbladder), ruptured urinary bladder (uroabdomen), right sided heart failure, thromboembolism (clots), cancer , liver failure, among others.