Evaluation of canine small intestinal permeability using the lactulose/rhamnose urinary excretion test

The use of the lactulose and rhamnose urinary excretion test was evaluated in dogs with gastrointestinal disease. Lactulose and rhamnose urinary excretion was measured in three groups of dogs: clinically healthy dogs and dogs with gastrointestinal disease with and without coexistent panhypoproteinaemia. A significant increase in both the percentage of lactulose:percentage of rhamnose urinary excretion ratio and the percentage of lactulose excretion was demonstrated in dogs with hypoproteinaemia when compared to the other two groups. The results suggest that the lactulose/rhamnose urinary excretion test may prove a useful adjunct to currently available tests for assessing small intestinal function, but lacks sensitivity in detecting small intestinal mucosal damage in the absence of villus atrophy.