Syndrome of Undifferentiated Recurrent Fevers (SURF) is a disease with fevers of unknown origin. It burdens families financially and emotionally when a child must stay home. We believe SURF includes different groups. We aim to identify those groups to make the diagnosis of SURF easier and find the best treatments for SURF patients. This will be the largest SURF study to date. 115 enrolled patients will come from Cincinnati Children’s Hospital Medical Center, Texas Children’s Hospital, University of Michigan Medical Center, and Boston Children’s Hospital. The study will look at symptoms during fever episodes and markers of inflammation in the blood. The information will be analyzed for group patterns, the characteristics of each group, and treatments specific to each. Doing this research will help us better understand SURF so patients’ lives can go back to normal faster.