Questions and answers on the role of fecal lactoferrin as a biological marker in inflammatory bowel disease.

Among the available fecal biomarkers for the diagnosis and monitoring of inflammatory bowel disease (IBD), only calprotectin and lactoferrin have translated into useful clinical tools. Lactoferrin can be detected using simple and cheap techniques and it has excellent stability in feces over a long period of time. Fecal lactoferrin has a good diagnostic precision for separating organic and functional intestinal disease. However, a negative fecal lactoferrin test should be interpreted merely as the absence of significant neutrophilic intestinal inflammation. The mean sensitivity and specificity of the fecal lactoferrin determination for the diagnosis of IBD is 80% and 82%, respectively. Some studies have suggested a lower accuracy of lactoferrin when compared with calprotectin for the diagnosis of IBD, indicating that more studies on this topic are necessary. A parallel between fecal lactoferrin levels and IBD activity estimated with clinical, endoscopic, and histological parameters has been confirmed. However, this correlation seems to be lower in Crohn's disease than in ulcerative colitis, mainly when Crohn's disease patients with purely ileal disease are considered. Fecal lactoferrin determination may be useful in predicting impending clinical relapse in IBD patients. Fecal lactoferrin may be a helpful noninvasive diagnostic tool for monitoring therapeutic efficacy, mainly on mucosal healing, as a decreasing concentration of lactoferrin can be interpreted as a marker of therapeutic response. Finally, in patients with Crohn's disease who have undergone ileocolonic resection, those with higher lactoferrin fecal levels might be more prone to postsurgical recurrence.