Feasibility of a Minimally Invasive Diagnostic Algorithm in Suspected Crohn's Disease

Inclusion Criteria:

• Clinical suspicion of CD*

• Age 18-40 years

• Signed informed consent

*A clinical suspicion of CD is based on the following definition:

• Diarrhea and/or abdominal pain for more than 1 month (or repeated episodes ofdiarrhea and/or abdominal pain) and either

• fecal calprotectin ≥ 200 mg/kg or

• fecal calprotectin ≥ 50 mg/kg plus one or more of the following findings:

• C-reactive protein (CRP) > 5 mg/L

• Thrombocytosis (> 400 x 109/L)

• Anemia (hemoglobin < 7.0 mmol/L for women and < 8.0 mmol/L for men or a decrease > 0.5 mmol/L compared to the usual level)

• Prolonged fever (> 37.5 ◦C for more than 2 weeks)

• Weight loss (≥ 3 kg or ≥ 5% compared to the normal body weight)

• Perianal abscess / fistula

• Family history of inflammatory bowel disease.

Exclusion Criteria:

• Previous intestinal resection

• Positive serologic markers for celiac disease

• Positive stool polymerase chain reaction for pathogenic bacteria

• Positive stool polymerase chain reaction for intestinal parasites

• Suspected or established acute bowel obstruction (ileus)

• Intake of NSAIDs or acetylsalicylic acid ≤ 4 weeks before inclusion, exceptlow-dose, prophylactic acetylsalicylic acid (≤ 150 mg per day)

• Intake of opioid or opioid-like medications ≤ 1 week before inclusion

• Pregnancy or lactation

• Inability to comply with protocol requirements, e.g. for reasons including alcoholor recreational drug abuse

• Known gastrointestinal disorder other than functional gastrointestinal disorders

• Renal failure defined by a plasma-creatinine above the normal reference range