The purpose of this study is to confirm the sensitivity and specificity of the BÜHLMANN fCAL™ ELISA as an aid in diagnosis to differentiate between Inflammatory Bowel Disease (IBD; Crohn's Disease (CD), Ulcerative Colitis (UC), or indeterminate colitis) and Irritable Bowel Syndrome (IBS).

To estimate the predictive value of a positive test (positive predictive value (PPV)) and the predictive value of a negative test (Negative Predictive Value (NPV)) using the proposed test outcomes for BÜHLMANN Calprotectin Test results when used in patients referred for diagnostic evaluation with signs and symptoms suggestive of either IBS or IBD.

To confirm the inter-laboratory consistency of test results for the BÜHLMANN fCAL™ ELISA.

To provide exploratory observations of test results in patients between the age of 2 and 21 years.

To provide a sample set from normal subjects with no symptoms or signs of gastrointestinal disease for use in Expected Value Testing.

Inclusion Criteria:

1. Adults or pediatric patients evaluated by a gastroenterological service for investigation of possible inflammatory intestinal disease or IBS. Patients are referred for sub-specialty evaluation of symptoms such as abdominal pain, diarrhea, altered appetite, weight loss, or anemia.

   • IBD: Eligible subjects will be analyzed as patients with IBD after a confirmed diagnosis of Inflammatory Bowel Disease (CD, UC, or Indeterminate Colitis), based on endoscopy and confirmed by histology of biopsies taken during endoscopy.
   • IBS: Eligible candidate subjects can also include patients who are self-referred with the relevant constellation of complaints. Eligible subjects will be enrolled after having a diagnosis of IBS based on the Rome III criteria confirmed by negative endoscopy including the colon and terminal ileum.
   • other GI Disorders: Eligible subjects will be enrolled after having a diagnosis of a gastrointestinal disorder other than IBD or IBS, confirmed by endoscopy results and other appropriate diagnostic studies.
   • Healthy Controls: Adults (≥22) with no abdominal complaints and no history of IBS, IBD or other chronic intestinal disorder, confirmed by medical history and physical examination at enrolment.

2. Individuals of either gender, ≥22 years of age (adult samples) or 2 to -21 years of age (pediatric samples).

3. IBD patients whose diagnostic endoscopy occurred within the previous month.

4. Individuals able to understand the study and the tasks required, and who sign the Informed Consent Form (adult subjects; ICF) or whose parent/guardian provides consent (ICF) and, if age 7-to-18 years of age, who provide assent (pediatric subjects).

Exclusion Criteria:

1. Individuals unable or unwilling to provide a stool specimen.
2. Individuals with known intestinal cancer, intestinal infection, upper gastrointestinal disease
3. Individuals receiving chemotherapy or systemic immunosuppressive drugs.
4. Individuals who have taken, within the previous 2 weeks, protein pump inhibitors or H2-receptor antagonists.
5. Individuals with previously diagnosed Inflammatory Bowel Disease managed with immunomodulators, 5-ASA (5-aminosalicylic acid) or biologic therapies or who have undergone a surgical resection or diversion procedure.
6. Individuals who have taken NSAIDs (nonsteroidal anti-inflammatory drugs), including aspirin, on 7 or more days during the 2 weeks before providing the sample.

100 adult subjects with Inflammatory Bowel Disease or Irritable Bowel Syndrome each have provided a stool sample. In addition, 50 pediatric subjects, age 2 years to 21 years, 25 subjects in each diagnostic group (IBD, IBS) will be enrolled. Recruitment of 120 normal subjects who will provide samples.