What could cause high glucose levels in urine other than diabetes?

Glucosuria. Glucosuria - glucose in the urine. If blood glucose is normal & kidneys are functioning appropriately the urine usually contains no glucose. An uncommon and unconcerning inherited condition called renal glucosuria spills glucose into urinr. A new group of medications mimics this inherited condition. Fanconi's syndrome also has glucosuria, many different things can cause this syndrome. See a doctor.