The test is based on a protein excreted in the urine by patients who have an infection in the appendix. Led by Dr. Richard Bachur, chief of emergency medicine at Children’s Hospital Boston, researchers discovered the hallmark protein by collecting and analyzing urine samples from 12 pediatric patients with confirmed cases of appendicitis (determined by inspection of the appendix after surgery). From an initial result involving thousands of different proteins, researchers narrowed the potential candidates by comparing the 12 samples to those from healthy children without appendicitis. “We analyzed the proteins to see which were statistically significant compared with [the controls], and this gave us a short list,” explains Hanno Steen, director of the Proteomics Center at Children’s and a co-author of the study. That short list, combined with other possible protein candidates identified in previous research on the subject, comprised 57 different possibilities.Appendicitis is the most common surgical emergency in children, but the diagnosis can be challenging. An incorrect diagnosis can either lead to unnecessary surgery or a ruptured appendix with serious complications.From this study, the researchers identified seven biomarkers linked with appendicitis. Of these, leucine-rich alpha-2-glycoprotein appeared to be the best — with few false-positive or false-negative results.