Glucose, Urine

The Glucose, Urine test (also called a urine glucose or glucosuria test) is used to identify and monitor diabetes mellitus and to gauge the effectiveness of antidiabetic therapy. It also assists in evaluating renal tubular function and recognizing renal glucosuria, and it is applied when endocrine conditions with excess counterregulatory hormones are suspected. In pregnancy care, the urine sugar test may be used to detect gestational glucosuria and to prompt further assessment for hyperglycemia or possible tubular dysfunction.

Glucose is freely filtered at the glomerulus and is normally almost completely reabsorbed in the proximal tubules. Glucosuria develops when plasma glucose exceeds the renal threshold (hyperglycemia) or when proximal tubular reabsorptive capacity is impaired. Renal causes include primary tubular defects such as Fanconi syndrome and primary renal glucosuria, as well as secondary tubular injury from conditions like glomerulonephritis, renal failure, or toxic injury. Gestational glucosuria may occur, most often in late pregnancy. Hyperglycemia-related glucosuria can accompany states of excess counterregulatory hormones and may be seen with exogenous glucocorticoids, thyroid hormone therapy, or somatropin, as well as with hormone-producing tumors. Persistent or marked glucosuria warrants clinical correlation and confirmation with blood glucose.