24 Hour Urine Glucose

Reference-interval

Glucose may appear in the urine at different blood glucose levels, varying in individuals. The blood level, glomerular blood flow, tubular reabsorption rate, & urine flow influence its appearance. Glucosuria usually occurs when the blood level is more than 180 to 200 mg/dL.
In the ACA urine glucose method, hexokinase (HK) catalyzes the phosphorylation of glucose by adenosine-5'-triphosphate ( ATP) to glucose-6-phosphate, which is oxidized to 6 phosphogluconolactone by glucose-6-phosphate dehydrogenase ( G6PD) with simultaneous reduction of nicotinamide-adenine dinucleotide phosphate ( NADPH). One mole of NADP is reduced to one mole of NADPH for each mole of glucose present. The absorbance due to NADPH (and thus the glucose concentration) is determined using a two filter (340-383 nm) end-point technique.

The appearance of glucose in the urine is regraded as a hallmark of diabetes mellitus, although this alone is not diagnostic. The 24-hour urine glucose measurement is useful for monitoring patients with diabetes. It represents a defined longer time period, & with blood levels of glycosylated hemoglobin, it contributes to the regular overall long-term management of the disease.

2 mL aliquot of a 24-hour urine collection. Proper 24 hour urine collection procedure should be followed, & collection container should be refrigerated at 2-6 C during collection. Upon receipt in the work area, it should be well-mixed & measured in a graduated cylinder. The total volume should be recorded.

Kaplan, Lawrence A. & Pesce, Amadeo J., Clinical Chemistry: Theory, Analysis, & Correlation, 2nd Edition, The C.V. Mosby Company, St. Louis, MO, 1989, pp. 450-451.
Henry, John Bernard, M.D., Clinical Diagnosis & Management by Laboratory Methods, 18th Edition, W.B. Saunders Company, Philadelphia, PA, 1991, pp. 404-406.
ACA IV Discrete Clinical Chemistry Analyzer Instrument Manual, Volume 3A, Chapter 6: Test Methodology, GLU 1.

24 hour urine glucose