Disclosed are methods for conducting diagnostic tests for the detection of the inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis. Also described are methods for monitoring a patient by administering tests of the present invention. Also described are methods for monitoring patient's treatment by administering tests of the present invention. Also described are methods for evaluating the effectiveness of a drug or a drug candidate by administering tests of the present invention to samples from patients, animal models, and cell cultures treated with a drug or a drug candidate. Also disclosed are methods for determining the usefulness of analytes, e.g. cytokines, for acting as diagnostic and monitoring markers for inflammatory bowel disease in the various methods of the invention.