A new, highly sensitive assay for C-reactive protein can aid the differentiation of inflammatory bowel disorders from constipation- and diarrhoea-predominant functional bowel disorders

• Published in: European journal of gastroenterology & hepatology Vol. 14; no. 4; p. 409
• Main Authors: Poullis, Andrew P, Zar, Sameer, Sundaram, Krishna K, Moodie, Simon J, Risley, Paul, Theodossi, Andrew, Mendall, Michael A
• Format: Journal Article
• Language: English
• Published: England 01.04.2002
• Subjects: Adult; C-Reactive Protein - analysis; Colonic Diseases, Functional - diagnosis; Constipation - etiology; Diagnosis, Differential; Diarrhea - etiology; Enzyme-Linked Immunosorbent Assay - methods; Female; Humans; Inflammatory Bowel Diseases - diagnosis; Male; Prospective Studies; ROC Curve; Sensitivity and Specificity
• ISSN: 0954-691X
• DOI: 10.1097/00042737-200204000-00013

Patients presenting to gastroenterology clinics with symptoms suggestive of lower-bowel disorders often require extensive investigation to differentiate functional from organic disease. C-reactive protein (CRP) is a sensitive marker of systemic inflammation. Levels of CRP are frequently raised in cases of inflammatory bowel disease (IBD). However, using conventional assays, not all cases of IBD have a detectable level. To determine whether a new highly sensitive CRP enzyme-linked immunosorbent assay (ELISA) can aid the differentiation between IBD and functional bowel disorders (FBDs) in gastroenterology outpatients presenting with lower-bowel symptoms. Serum was taken from 224 subjects attending a gastroenterology outpatient clinic. Of these, 203 were new patients and 21 were follow-up patients with quiescent colitis. The serum was analysed using a sensitive in-house ELISA. All new patients had a rigid sigmoidoscopy and rectal biopsy. Patients were investigated as deemed appropriate by the attending physician. Notes were reviewed after at least 6 months to determine the final diagnosis. A cut-off value of 2.3 mg/l had a sensitivity of 100% and a specificity of 67% in differentiating FBD from new cases of IBD. The geometric mean CRP was 0.383 mg/l in the constipation-predominant FBD group, 1.435 mg/l in diarrhoea-predominant FBD, 1.455 mg/l in quiescent IBD, 8.892 mg/l in newly presenting cases of ulcerative colitis, and 13.123 mg/l in newly presenting cases of Crohn's disease. A new, highly sensitive assay for CRP may help to distinguish FBD from IBD.