Embodiments of the invention provide method and devices for predicting the likelihood of acute appendicitis without invasive exploratory medical procedures. Several protein biomarkers: leucine-rich α-2-glycoprotein (LRG); S100-A8 (calgranulin); α-1-acid glycoprotein 1 (ORM); plasminogen (PLG); mannan-binding lectin serine protease 2 (MASP2); zinc-α-2-glycoprotein (AZGP1); Apolipoprotein D (ApoD); and α-1-antichymotrypsin (SERPINA3); are increased in the urine of patients with appendicitis. The method and devices comprise detecting the levels of these biomarkers and comparing with reference levels found in healthy individuals.