[Lactase deficiency in the intestinal mucosa. Demonstration by hydrogen detection in the expired air after lactose...

Lactose malabsorption can be demonstrated by detecting hydrogen (H2) in the expired air after oral loading with lactose. A comparative study was carried out on 24 subjects. Following an oral loading dose of lactose, the H2 eliminated during expiration was assayed by gas chromatography, and blood galactose levels were measured. The results showed that the test was reliable, well tolerated and reproductible. However, the method does not measure the amounts of lactase present in the intestinal mucosa. The lactose loading test seems to be valuable for studies on lactose and carbohydrate malabsorption.