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Principle: The detection is based on the glucoseoxidase-
peroxidase-chromogen reation. The oxidation of glucose by atmospheric oxygen is catalyzed by glucoseoxidase to form gluconic acid lactone and hydrogen peroxide. Peroxidase catalyzes the reaction of hydrogen peroxide with the chromogen. Apart from glucose, no other compound in urine is known to give a positive reaction.
Evaluation: Pathological glucose concentrations are indicated by a colour change from green to bluish green. Yellow or greenish test fields should be considered negative
or normal. All test fields which have an intensity greater than the greenish negative colour field must be considered positive. The colour fields correspond to the following ranges of glucose concentrations:
neg. (yellow), neg. or normal (greenish),
50, 150, 500 and ≥1000 mg/dl or
neg. (yellow), neg. or normal (greenish),
2.8, 8.3, 27.8 and ≥55.5 mmol/l.
An inhibitory effect is produced by gentisic acid. Falsely positive reactions can also be produced by a residue of peroxide-containing cleansing agents. For test strips that already feature the optimal protection against ascorbic acid, the glucose test is not influenced by vitamin C. These strips are marked in the ordering information. Other test strips may show false negative results with larger amounts of ascorbic acid in the sample.
Diagnosis: Because of the clear distinction between physiological and pathological glucosuria, the test is especially suitable for the detection of diabetes mellitus and for supervising (and self-supervising) of diabetes. Apart from diabetes mellitus, renal glucosuria with increased glucose concentrations may be noted during pregnancy, and after a meal with excessive carbohydrates. Every positive test reaction requires further diagnosis.
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