Levulozuria - the appearance of levulose (fruit sugar) in the urine, which is found in liver diseases, Wilson's disease, etc. The excretion of levulose in the urine when it is taken 50–100 g is ingested as a diagnostic hepatic test, since left liver lesions are assimilated only by the liver.
The test is positive for acute lesions of the hepatic parenchyma, chronic common processes. With hemolytic jaundice, it is negative.
In the case of mechanical blockage of the bile ducts, the sample may be positive, since acute retention of bile disrupts the absorption of fruit sugar by the liver cells. A levulose load cannot be a differential diagnostic test of various forms of jaundice.
Levulose is determined by the Selivanov reaction (fruit sugar with resorcin and hydrochloric acid gives a red color). Quantitative determination is made by a polarization saccharimeter (a levulose rotates the plane of polarization to the left).