Glycosuria exists:

Glycosuria exists:

• A. When blood glucose levels exceed the renal threshold for absorption of glucose
• B. When blood glucose levels are lower than the renal threshold for absorption of glucose
• C. When urine glucose levels are lower than the renal threshold for absorption of glucose
• D. When urine glucose levels are higher than the serum threshold for absorption of glucose

Answer: (A)

Glycosuria occurs when the amount of glucose in the blood exceeds what the kidneys can reclaim. Glucose is filtered by the kidneys and normally reabsorbed in the proximal tubule up to a maximum rate. When blood glucose rises high enough that the filtered load surpasses this reabsorptive capacity (the renal threshold for glucose), the extra glucose spills into the urine. That’s why you see glucose in the urine in conditions like uncontrolled diabetes or with tubular transport problems. If blood glucose stays below that threshold, all filtered glucose is reabsorbed and urine glucose remains absent. The idea of urine glucose being lower than a threshold or of comparing urine thresholds to serum thresholds isn’t how glycosuria is determined, since the critical point is the blood concentration exceeding the kidney’s reabsorptive capacity.

Glycosuria occurs when the amount of glucose in the blood exceeds what the kidneys can reclaim. Glucose is filtered by the kidneys and normally reabsorbed in the proximal tubule up to a maximum rate. When blood glucose rises high enough that the filtered load surpasses this reabsorptive capacity (the renal threshold for glucose), the extra glucose spills into the urine. That’s why you see glucose in the urine in conditions like uncontrolled diabetes or with tubular transport problems.

If blood glucose stays below that threshold, all filtered glucose is reabsorbed and urine glucose remains absent. The idea of urine glucose being lower than a threshold or of comparing urine thresholds to serum thresholds isn’t how glycosuria is determined, since the critical point is the blood concentration exceeding the kidney’s reabsorptive capacity.