Glucose — Normal Range & Interpretation
Urine glucose detects glucosuria on a standard dipstick urinalysis. The proximal tubule reabsorbs filtered glucose completely until the serum level exceeds the renal threshold of approximately 180 mg/dL, at which point glucose spills into the urine. A negative result is the expected finding in healthy patients, and any positive reading signals either hyperglycemia or a tubular reabsorption defect.
| Male | Female | Unit | Category |
|---|---|---|---|
| Negative | Negative | — | Urinalysis |
Clinical Context
Urine glucose detects glucosuria on a standard dipstick urinalysis. The proximal tubule reabsorbs filtered glucose completely until the serum level exceeds the renal threshold of approximately 180 mg/dL, at which point glucose spills into the urine. A negative result is the expected finding in healthy patients, and any positive reading signals either hyperglycemia or a tubular reabsorption defect.
The most common cause of a positive urine glucose is uncontrolled diabetes mellitus, where serum glucose surpasses the renal threshold. Stress hyperglycemia, corticosteroid therapy, pancreatitis, Cushing syndrome, and acromegaly also produce glucosuria. Glucosuria with a normal serum glucose points to proximal tubular dysfunction, including Fanconi syndrome, pregnancy-related lowering of the renal threshold, and SGLT2 inhibitor therapy. A negative urine glucose does not rule out diabetes because early or well-controlled disease stays below the spill point.
Board-style questions on urine glucose pair the renal threshold value of 180 mg/dL with the expectation that urine glucose correlates with serum hyperglycemia. Questions link a positive dipstick to new-onset diabetes screening with a fasting glucose or A1C. Expect items that identify SGLT2 inhibitors and pregnancy as causes of glucosuria with euglycemia, and items that reinforce serum testing as the diagnostic standard over urine dipstick for diabetes.
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