II. Definitions
- Renal Threshold for Glucose (RTg)
- RTg is the Serum Glucose level above which Glucose spills into the urine and is not reabsorbed
- Glucose reabsorption is mediated by Sodium-Glucose Cotransporter 2 (SGLT-2) at the proximal tubule
- Above the RTg, SGLT-2 is overwhelmed and cannot absorb additional Glucose
- RTg >170 to 200 mg/dl (typically listed as 180 mg/dl) in non-diabetic patients
- RTg >200 to 250 mg/dl in Type 2 Diabetes Mellitus
- Osaki (2016) J Diabetes Investig 7(5):751-4 +PMID: 27181936 [PubMed]
III. Causes: Hyperglycemia Causes of Glucose in urine
- See Hyperglycemia
IV. Causes: Renal Causes of Glucose in the urine
- Signs suggestive of Renal Tubular disease
- Serum Glucose <180 mg/dl
- Glucose Tolerance Tests are normal
- Ketosis absent
- Specific Causes
- Fanconi Syndrome
- Glycosuria despite a normal Serum Glucose
- Associated with multiple Electrolyte abnormalities
- Pregnancy
- SGLT2 Inhibitor (Sodium-Glucose Co-Transporter-2 Inhibitor)
- Toxic renal tubular disease
- Inflammatory renal disease
- Increased GFR without tubular damage
- Fanconi Syndrome
V. Causes: False PositiveGlucose on Urinalysis
- Ascorbic Acid
- Nalidixic Acid
- Cephalosporins
- Probenacid
- Ketones
- Levodopa
VI. Causes: False NegativeGlucose on Urinalysis
- Increased Urine Specific Gravity
- Uric Acid
- Vitamin C
- High Urine pH