Diagnostic advances in inflammatory bowel disease (imaging and laboratory).

Autoimmune and antimicrobial antibodies currently play only an adjunctive role in the diagnosis of inflammatory bowel disease (IBD). Their sensitivity and specificity are not high enough to be relied upon alone to secure a diagnosis; however, their most promising role seems to be in identifying Crohn's disease patients at a higher risk of progression to intestinal complications. Serum C-reactive protein (CRP) correlates well with other measures of biologic activity but not as well with clinical activity. CRP can help predict IBD relapses, and in patients with severely active ulcerative colitis may indicate which patients are most likely to progress to colectomy. Similarly, fecal lactoferrin and calprotectin are reasonably accurate and noninvasive measures of disease activity, can predict relapse, and identify a high-risk group among acute severe colitis patients. Capsule endoscopy is a highly sensitive tool that can be used in patients with suspected Crohn's disease with a negative traditional workup, but lower specificity and the risk of capsule retention preclude first-line use. CT enterography can delineate the extent and severity of bowel inflammation and detect extraluminal findings. Magnetic resonance enterography is a radiation-free cross-sectional imaging alternative that is comparable to CT enterography in diagnostic accuracy.