Population screening for the human adult lactase phenotypes with a multiple breaths version of the breath hydrogen test.

Lactose tolerance tests with conventional blood glucose determination and with breath hydrogen analysis after storage of breath samples in aluminium aerosol cans were simultaneously performed in 60 healthy adult subjects. Both tests were equally reliable in the diagnosis of the lactase phenotype in healthy persons. In subjects with decreased glucose metabolism the breath hydrogen test seems to be more reliable than the blood glucose test. Provisions for storing breath samples for up to several weeks, avoidance of invasive procedures, and insensivity to glucose absorbed during the test make the present version of the lactose tolerance test with breath hydrogen determination particularly suitable for population studies.