glucose in 24 hour urine
Reference interval
- 0-50 mg/24 hours
Principle
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.
Clinical significance
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.
Increases
Specimen
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.
More general terms
Additional terms
References
- ↑ 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.
- ↑ Panel of 7 tests Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0020476.jsp