Reverse isotope dilution assay and lactose intolerance assay

摘要

A "reverse isotope dilution assay" herein, wherein a pathway that produces a given metabolite is assayed by diluting a labelled metabolite produced by a second constitutive pathway. In one aspect, the invention relates to a method for monitoring lactose maldigestion or lactose intolerance in humans. Specifically, the method requires administering a reverse tracer of labeled glucose and unlabeled lactose to an individual and assessing labeled carbon dioxide in breath or blood. If the lactose is digested, the labeled CO₂ produced by the labeled glucose is diluted by the metabolism of the lactose.