Results: The median level of LRG1 in serum was significantly higher in the group of children with pathohistologically confirmed acute appendicitis than in the control group, at 350.3 μg/mL (interquartile range (IQR) 165.2–560.3) and 25.7 μg/mL (IQR 14.7–36.8) (p < 0.001), respectively. This evidence concerns the gene LRG1 and appendicitis.