To begin addressing these questions, we measured GDF15 levels in 40 serum samples from septic patients and compared the results with those of 130 healthy controls (HC) and 33 patients with a histological diagnosis of acute appendicitis (AA; including 20 diagnosed with acute phlegmonous appendicitis and 13 with acute gangrenous appendicitis) before surgery. The gene discussed is GDF15; the disease is appendicitis.