 Even with a full battery of tests, it may not be possible to diagnose Crohn's with complete certainty; a colonoscopy is approximately 70% effective in diagnosing the disease, with further tests being less effective.Disease in the small bowel is particularly difficult to diagnose, as a traditional colonoscopy allows access to only the colon and lower portions of the small intestines; introduction of the capsule endoscopy aids in endoscopic diagnosis.Giant (multinucleate) cells, a common finding in the lesions of Crohn's disease, are less common in the lesions of lichen nitidus.