Assessment of intestinal permeability with a two-hour urine collection.
The differential urinary excretion of orally administered lactulose and mannitol is used to evaluate intestinal permeability. This test usually involves a 5- to 6-hr urine collection. We hypothesized that a shorter collection time would give an equivalent result. Forty-three patients with a variety of gastrointestinal symptoms and diagnoses (group 1) and 42 patients with Crohn's disease (group 2) had a standard lactulose/mannitol permeability test. The lactulose and mannitol urinary excretion was calculated using the first urine (group 1) or the 1-hr and 2-hr urine (group 2) and was compared to the values calculated from the routine 5- or 6-hr collection. Lactulose excretion kinetics, expressed as the percent of the total urinary excretion within a given time period, were as follows: 21% in first hour (group 2), 29% in second hour (group 2), and 46% in first 2.5 hr (group 1). Mannitol urinary excretion kinetics were 16%, 31%, and 44%, respectively. The lactulose/mannitol ratio based on a standard urine collection correlated well with the ratio based on just the first urine produced by the patient (R2 = 0.94; P < 0.001; group 1) and the 2-hr urine (R2 = 0.464; P < 0.001; group 2). Future use of the lactulose/mannitol ratio to assess intestinal permeability may be able to be simplified by shortening the urine collection time.
Akram
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Department of Medicine, Ben Taub Hospital, Baylor College of Medicine, Houston, Texas 77030, USA.
Mourani
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Ou
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Rognerud
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Sadiq
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Goodgame
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D000284:Administration, Oral; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000503:physiopathology*; D007421:Intestine, Small / Q000503:physiopathology*; D007792:Lactulose / Q000008:administration & dosage / Q000652:urine*; D008297:Male; D008353:Mannitol / Q000008:administration & dosage / Q000652:urine*; D008875:Middle Aged; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors
D008353:Mannitol; D007792:Lactulose