UTILITY OF A RAPID FECAL LATEX AGGLUTINATION-TEST DETECTING THE NEUTROPHIL PROTEIN, LACTOFERRIN, FOR DIAGNOSING INFLAMMATORY CAUSES OF CHRONIC DIARRHEA

Objective: The utility of tests for fecal neutrophils in the setting o f chronic diarrhea has not been established. The purpose of this study was to determine the causes of chronic diarrhea associated with fecal neutrophils. Methods: One fecal specimen from each of 10 normal subje cts, 26 patients with known microscopic colitis, 13 with celiac sprue, eight with Crohn's disease, four,vith ulcerative colitis, and 103 wit h chronic diarrhea of unknown origin, as well as 10 fecal specimens fr om a patient with chronic nongranulomatous enterocolitis were analyzed blindly for the presence of a neutrophil granule protein called lacto ferrin using a commercial latex agglutination kit, Diagnostic evaluati on of the 103 patients with chronic diarrhea was carried out to determ ine the diagnostic accuracy of this test for chronic inflammatory bowe l disease. Results: None of the normal control subjects, three of 39 p atients with microscopic colitis or celiac sprue, all 10 specimens fro m the patient with enterocolitis, and all 12 control patients with ulc erative colitis or Crohn's disease had a positive fecal lactoferrin te st. Eleven of 103 patients with chronic diarrhea presenting without a diagnosis had a positive test, and all were diagnosed with an inflamma tory condition of the colon (five-, ulcerative colitis; four-, Crohn's disease; one-, ischemic colitis; and one-, microscopic colitis). Only one patient with inflammatory bowel disease had a negative lactoferri n test. The sensitivity, specificity, and positive and negative predic tive values of the fecal lactoferrin test for ulcerative or Crohn's co litis were 90%, 98%, 82%, and 99%, respectively, Conclusion: The major cause of fecal neutrophils in patients with chronic diarrhea is chron ic inflammatory bon el disease of the colon. The latex agglutination t est for fecal lactoferrin offers a highly sensitive, specific, and sim ple means for detection of fecal neutrophils in these patients. (Am J Gastroenterol 1998;93:1300-1305. (C) 1998 by Am. Coll. of Gastroentero logy).