Avalia？？o da interferência do ácido ascórbico na detec？？o da glicosúria

introduction: ascorbic acid (vitamin c) is commonly used as a vitamin supplement. it is a water soluble vitamin, which is excreted through urine and may interfere in laboratory tests as well as redox reactions for urinary glucose detection. objective: this study aims to assess ascorbic acid interference in glycosuria detection by dry chemistry method (reagent strips). material and methods: urine samples were evaluated by using clinitek atlas chemistry analyzer (siemens healthcare diagnostics inc., usa). four urine samples with different glucose concentrations were selected: 100 mg/dl, 250 mg/dl, 500 mg/dl and > 1,000 mg/dl. 5 aliquots were created for each glucose concentration and a solution of ascorbic acid 200 mg/dl was added, sufficient to obtain a final ascorbic acid concentration of 20 mg/dl in the first tube, 50 mg/dl in the second tube, 270 mg/dl in the third tube, 1,000 mg/dl the fourth tube, and 2,000 mg/dl in the fifth tube. after the addition of ascorbic acid, the samples were reassessed by using clinitek atlas chemistry analyzer. results: there was no interference at concentrations of 20 mg/dl. however, there was ascorbic acid interference at concentrations higher than or equal to 50 mg/dl, which was characterized by false-negative results for urinary glucose detection. conclusion: the results corroborated the interference of ascorbic acid in dry chemistry method (reagent strips) inasmuch as it underestimates urinary glucose levels.