Assessment of optimal dose of lactose for lactose hydrogen breath test in Indian adults.

To evaluate the possibility of using a 12.5 g or 25 g oral dose of lactose for hydrogen breath test for diagnosis of lactose intolerance instead of the usual 50 g dose. 35 patients with non-ulcer dyspepsia and an abnormal 50 g lactose breath hydrogen of more than 20 ppm over the base line were retested using 12.5 g and 25 g lactose. 32 (91.4%) and 15 (42.8%) of these 35 patients had an abnormal hydrogen breath test using 25 g (p = ns compared to 50 g dose) and 12.5 g (p < 0.001) lactose doses respectively. This study reveals that it may be possible to use a 25 g lactose dose instead of a 50 g dose for the lactose hydrogen breath test.