Clinical evaluation of a lateral flow test for the detection of elevated fecal lactoferrin as an indicator of intestinal inflammation

Abstract

Background: Human lactofernn, an 80 KD glycoproteni, is a component of neutrophil secondary granules and is found m the secretions hydrating mucosal membranes. Duaing intestinal inflammation, activated neutrophils migrate into the lumen and a measurable increase of fecal lactoferrin (FLA) can be detected. Previous studies have demonstrated that elevated FLA can discnminate patients with active inflammatory bowel disease (IBD) from FLA levels measured in a healthy control population as well as in inactive IBD and in patients vath imtable bowel syndrome (IBS). Aim: To validate a qualitative lateral flow FLA assay developed as a rapid tool for use in physicians' offices for the evaluation and interval assessment of patients with symptoms of IBD and IBS. Methods: FLA was measured quantitatively and qualitativdy in 79 fecal specimens from IBD and IBS patients. The study population was eompnsed of 58 Crohn's disease (CD), 18 ulcerative colitis (UC) and 3 IBS patients with an age range of 4 to 51 yrs and gender ratio of 1 to 2.5 (male to female). FLA (ug/g feces) was determined by ELISA using a standard curve of purified lactoferrin. Qualitative analysis for elevated lactoferrin was done by ELISA (IBD-CI-IED using an absorhance cutoff of 0.2 and visually by lateral flow. Active disease was defined by an elevated FLA of 8ug/g feces. Results: FLA was elevated in 48 of 74 specimens tested from IBD patients. FLA measured in patients with active CD and UC was 278 + 0.36 and 1217-+ 534, respectively (mean-+ SE). In contrast, FLA measured in feces from patients with inactive CD, UC and IBS was 1.43 + 0.35, 4.07 -+ 0.99 and 1.83 -+ 0.51, respectively. The lateral flow assay displayed a sensitivity, specificity and overall correlation for detecting an FLA greater than/equal to 8ug/ g feces (indicative of active intestinal inflammation) of 100, 94 and 98%, respectively. Conclusion: Our results demonstrate that the lateral flow assay performs equivalently to the IBD-CHEK in screening for the presence of intestinal inflammation. This test is a simple ten minute assay, making it suitable for use in the physicians' office/clinic setting.