Lactoferrin Assessment of Rectal Effluent as an Aid to Colonoscopy for Determining Intestinal Inflammation

Abstract

Purpose: Accurate evaluation of intestinal inflammation is vital in the management of inflammatory bowel disease (IBD) patients. A limitation of conventional colonoscopy is the inability to visualize the entire intestinal tract. Fecal lactoferrin, a marker of intestinal inflammation, may function as an aid to colonoscopy for assessing IBD patients. Our aim was to evaluate lactoferrin levels in rectal effluent in conjunction with colonoscopy to assess the presence of inflammation in IBD patients undergoing screening or diagnostic colonoscopy. Methods: Fifty-nine adult IBD patients from a single tertiary care center were enrolled. Each subject provided a sample of the effluent passed towards the end of the bowel preparation procedure prior to colonoscopy. The specimens were screened for elevated lactoferrin using the IBD-CHEK®, a commercially available enzyme-linked immunosorbent assay (ELISA) (TechLab, Blacksburg). There were 27 active patients and 32 inactive patients based on colonoscopy and histology. Results: Forty-four Crohn's disease (CD) and 15 ulcerative colitis patients were included in the study. The median age was 44 (22–72) and there were 42 females and 17 males. The lactoferrin ELISA had 74.1% sensitivity, 84.4% specificity, and 79.7% correlation with colonoscopic findings. Five patients characterized as inactive by colonoscopy had moderately high lactoferrin levels. Four of these patients had Crohn's disease, and the elevated lactoferrin may represent inflammation unseen by conventional colonoscopy. This suggests a role for lactoferrin testing to help target CD patients requiring additional testing such as small bowel radiography. Seven samples with endoscopically defined inflammation were negative on the lactoferrin ELISA. Conclusion: Rectal effluent samples are easily obtained with a relatively high degree of patient compliance. Testing for lactoferrin provides an aid to colonoscopy for determining intestinal inflammation. A positive lactoferrin result in an endoscopically inactive patient may indicate unresolved inflammation but further investigation is needed. A negative result in an effluent sample is not clinically relevant due to the potential dilution of lactoferrin during the bowel preparation procedure and should not be used to rule out the presence of intestinal inflammation.