Abstract
Ascorbic acid is well known to give false negative results in the clinical determination of urinary glucose or occult blood (blood/hemoglobin) using commercially available reagent test strips. We describe herein a procedure to remove the ascorbic acid interference with use of a newly deviced enzyme reactor, where ascorbate oxidase is immobilized on the inner surface of polystyrene test tubes treated with a silane coupling reagent. It was clearly shown that even the highest possible concentration of ascorbic acid in urine can be completely oxidized within a few minutes at room temperature by the enzyme reactor, and therefore urinary glucose or occult blood can be determined without any false negative results.
This type of enzyme reactor may be applicable for use in many clinical fields and in many testing situations in clinical laboratories to improve the accuracy and reliability of clinical tests.
