Evaluation of a New Latex Agglutination Test for Fecal Lactoferrin in Travelers' Diarrhea.

The detection and diagnosis of travelers' diarrhea by fecal culture method, often insensitive, expensive, and time consuming, could well be replaced with the latex agglutination test to detect fecal lactoferrin. As an initial screening, this test could be useful to differentiate between those patients who are more likely to have an invasive enteropathogen and those patients requiring antidiarrheal chemotherapy only. Fecal samples from 92 patients with travelers' diarrhea were tested for occult blood, fecal leukocytes, and fecal lactoferrin at stool dilutions of 1:50 and 1:200. The results were compared with findings from fecal cultures for enteropathogens. Statistical analyses were performed measuring the performance of the latex agglutination test for fecal lactoferrin to calculate its sensitivity, specificity, and positive and negative predictive values. Invasive pathogens were identified in 36 (39%), and a noninvasive pathogen was found in 18, or 20%, of the cases. At the stool dilution of 1:50, fecal lactoferrin showed more sensitivity than did leukocytes or occult blood in detecting the presence of invasive enteropathogens and, with a negative predictive value of 94%, was superior in predicting their absence. At the 1:200 dilution, a lower sensitivity of 55%, but a higher specificity of 82%, compared to 55% with the 1:50 dilution, was demonstrated. The determination of fecal lactoferrin might prove to be more useful and less expensive and time consuming as an initial screening for patients presenting with travelers' diarrhea. Further evaluation and antibacterial treatment could, therefore, be reserved for those with a positive lactoferrin test.