Glucosuria in an adult not treated for diabetes most likely points to either undiagnosed diabetes or an impaired renal threshold for glucose. The kidneys normally reabsorb most filtered glucose until their transport capacity is reached; when blood glucose rises above about 180 mg/dL, glucose begins to spill into the urine. If someone isn’t being treated for diabetes but has glucosuria, it raises concern that blood glucose may be elevated with undiagnosed diabetes. It could also reflect a renal glycosuria condition, where the kidneys don’t reabsorb glucose properly even if blood glucose isn’t extremely high. Either way, this finding warrants evaluation with blood glucose testing (such as fasting glucose or HbA1c) and assessment of kidney function. Dehydration or hyperthyroidism aren’t typical primary causes of glucosuria in this context.