a method is described for the rapid , sensitive and accurate determination of sucrose in biological fluids . a substrate is pre - coated with a glucose or fructose polymer and a transglycosidase enzyme . when the coated substrate is incubated with biological fluids containing concentrations of sucrose , the transglycosidase enzyme transfers monomers of glucose or fructose from the sucrose to the glucose or fructose polymer . the dimensions of the polymer are increased in proportion to the sucrose concentration of the samples . newly formed polymer is subsequently quantitated in an immunoassay which employs either a combination of a carbohydrate - binding protein and a conjugate of a secondary antibody and a marker enzyme , or a conjugate of a carbohydrate - binding protein and a marker enzyme . the assay is accurate at sucrose concentrations below 1 μg / ml . no interference was observed at glucose concentrations as high as 25 mm . the sucrose detection assay is particularly useful in a non - invasive diagnostic test for gastric damage .