A urine test with (++) ascorbic acid indicates (++) vitamin C, which means ascorbic acid is vitamin C. Elevated vitamin C in a routine urine test (++) is usually due to excessive vitamin C intake. Such as dietary use of fruits rich in vitamin C, intravenous infusions of vitamin C or oral vitamin supplementation. Vitamin C has no real significance in the urine, but if the concentration of vitamin C in the urine is elevated, it can lead to a false (-) test result. For example, nitrite can be reduced to (-) in an environment with high concentrations of vitamin C, and this results in a false (-) result. Or occult blood may show a (-) result in the presence of high vitamin C, and the resulting misdiagnosis. Therefore, vitamin C, also known as ascorbic acid, is added to the urine for comparison to exclude false (-) results due to vitamin C.