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Test principle
	Glucose is shown on an indicator system by a specific enzymatic reaction for glucose (glucose oxidase: GOD and peroxidase: POD).
In the first step of the reaction glucose is oxidised by atmospheric oxygen and catalysed by GOD to D-gluconolactone. In the second step, the chromogen is oxidated by hydrogen peroxide (under PODCanalysis) to form a dye (colour development from yellow (normal) to green to dark green-blue).

Sensitivity

The practical sensitivity for ascorbic acid free urines is approx. 40 mg/dl (2.2 mmol/l). The physiological limit value is around 15 mg/dl, (0.8 mmol/l).

Reference range:	Morning urine (fasting)	< 20 mg/dl (< 1.1 mmol/l)
	Daytime urine	< 30 mg/dl (< 1.7 mmol/l)

Specificity

The test is based on the glucose specific glucose oxidase/ peroxidase reaction. Other sugars do not react. Ketone bodies do not interfere.

Sources of error

Ascorbic acid in high doses can hamper the reaction in specimens with a low glucose content (up to 250 mg/dl) and so produce diminished results. In case of a positive ascorbic acid reaction the test should be repeated a day after reducing the vitamin-C intake. Falsepositive results can be caused by oxidising disinfectants. Gentisic acid or pH<5 can delay the colouration. High specific weight reduces the gravity to glucose.

Clinical significance

Apart from arterial sclerosis, diabetes is one of the most important common diseases. Early diagnosis and thus early treatment is of decisive importance, in order to delay or prevent subsequent consequences.The determination of glucose in urine has a high diagnostic importance for the early detection of diabetes mellitus and for monitoring the course of the disease and self-monitoring. However, it should be noted that some glucose metabolic disorders are not accompanied by glucosuria and on the other hand, glucosuria can have other causes than diabetes mellitus. Glucosuria results if the reabsorption level of glucose in the kidney is exceeded. In healthy persons, this renal threshold lies at a blood glucose level of approx. 150-180 mg/dl (8.3-10 mmol/l), it can increase with age. There is a large number of undetected diabetics (30-50% not identified). Glucose cannot normally be detected in urine, although minimum quantities are also eliminated by healthy kidneys. Colour changes weaker than the field for 50 mg/dl (2.8 mmol/l), should be classified as normal. The limit value for physiological glucosuria in morning urine is 15 mg/dl (approx. BE 0.8 mmol/l) 1,2). Renschler gives an upper limit of 30 mg/dl 3). The sensitivity (E90) of the test strips should lie close to the limit of physiological glucosurias. 3, 4) Due to the practical detection limit of 40mg /dl (approx. 2.2 mmol/l) for ascorbic acid free urines, the test strips reliably detect even slightly pathological glucosurias.

Without doubt, it is advantageous if the exceeding of the clinical decision range is accompanied by a clear change in colour, e.g. from yellow to green, as diabetics are often found to have weak eyesight. Within the important diagnostical decision-making range between normal and pathological a good semi-quantitative evaluation is achieved with the first comparison field, which is set to a value of 50mg/dl.

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Urine Diagnostics / Urine Test Strips / Portfolio Urine Test Strips / Glucose

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