The Hydrogen Breath Test to assess Fructose Malabsorption uses a challenge dose of fructose. The subject of an article published in Digestion examines what is the appropriate challenge dose. The researchers used challenge doses of 15, 25 and 50 grams of fructose. The results of the study were that a high percentage of the subjects were unable to tolerate the 50 gram dose although they exhibited no prior symptoms of Fructose Malabsorption. The researchers concluded that a 50 gram dose is inappropriate to characterize clinically significant Fructose Malabsorption. Metabolic Solutions uses a 25 gram challenge dose in its test.
Reference: Digestion. 2011 Sept 24; 84(4): 269-272