Glycosuria is the presence of glucose in the urine — the same condition as glucosuria, the two spellings reflecting different conventions for transliterating the Greek root for sugar. It occurs when blood glucose rises above the renal threshold (about 10 mmol/L) and the kidneys’ reabsorption transporters are overwhelmed, letting glucose escape into the urine. Persistent glycosuria is a hallmark of uncontrolled diabetes mellitus and was historically the basis of diagnosis — before blood tests, physicians tested urine for sweetness. Dipstick testing still provides a cheap, instant screen, though definitive diagnosis rests on blood glucose and HbA1c. Brief glycosuria can also follow a heavy sugar load or appear in pregnancy without indicating disease.