Urinary lactose tolerance test for the detection of lactose malabsorption

We investigated the frequency of hypolactasia by determining galactose excretion and galactose/creatinine ratios in two-hour urine collections after a standard loading of lactose in 47 healthy adult volunteers. Following overnight fasting, a solution containing 50 g of lactose was given. A urinary galactose level of less than 0.9 mmol/L was taken to indicate hypolactasia. Lactose malabsorption was determined in 83% of the volunteers. Urinary galactose levels were consistent with galactose/creatinine ratios.