1. A method for classifying whether a sample from an individual not having inflammatory bowel disease (IBD) is associated with irritable bowel syndrome (IBS), the method comprising: (a) measuring a concentration level of at least one marker in said sample, wherein said at least one marker comprises an anti-flagellin antibody; and (b) applying a combination of at least two learning statistical classifier systems to the measured concentration level of said at least one marker to classify said sample as an IBS sample or as a non-IBS sample.