Sc. Fleming et al., MEASUREMENT OF SUGAR PROBES IN SERUM - AN ALTERNATIVE TO URINE MEASUREMENT IN INTESTINAL PERMEABILITY TESTING, Clinical chemistry, 42(3), 1996, pp. 445-448
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.