MEASUREMENT OF SUGAR PROBES IN SERUM - AN ALTERNATIVE TO URINE MEASUREMENT IN INTESTINAL PERMEABILITY TESTING

The percentage dose of lactulose and mannitol excreted in urine after oral ingestion is used as a noninvasive method of assessing small inte stinal permeability. The collection of incomplete or inaccurately time d urine samples can lead to errors in estimation of sugar probe molecu les, We describe an HPLC method for the simultaneous determination of lactulose and mannitol in serum after oral ingestion of test sugars. W e applied the test to healthy volunteers and to subjects undergoing je junal biopsy for suspected gluten-sensitive enteropathy. The ratio of concentrations of lactulose and mannitol in serum discriminated well b etween subjects with a normal biopsy and those with villous atrophy, d iscrimination being best at 90 min postdose. The results agree well wi th lactulose:mannitol ratios determined in urine (r = 0.88), and the t wo methods ran be used interchangeably. The determination of mannitol and lactulose in serum provides an acceptable alternative to urine col lection and may be particularly useful in young children. It also redu ces the time spent on the investigation from 5 h to 90 min.