Glucose (Sugar, GLU)
Glucose is the main source of energy for all cells of the body.
Healthy adults have very small amounts of glucose in their urine which cannot be detected by standard urine tests performed at the laboratory. Therefore, a urinalysis should normally show no glucose in the urine of healthy adults.
The condition in which glucose is detected in the urine is called glycosuria. The appearance of glucose in the urine is generally caused by high blood sugar levels (such as in diabetes) or renal disorders. Rarely, physiological glycosuria occurs in healthy adults.
Glycosuria (sugar in the urine) causes small amounts of glucose in the urine and may occur due to eating a lot of carbohydrates when the body cannot absorb sugar temporarily, emotional tension and stress, or certain medications.
Kidneys remove toxins and waste products from the body. They filter our blood removing everything we do not need and absorbing everything we do. However, renal tubules can absorb only a limited amount of glucose into the bloodstream. When the blood glucose level exceeds this limit, the renal tubules become overwhelmed and begin to excrete glucose in the urine. This point is called the renal threshold of glucose (RTG) and it varies for different people. Pregnant women often have a low renal threshold of glucose which is why glucose may be found in their urine, especially in late pregnancy.
The condition in which kidneys cannot absorb glucose but blood glucose levels are normal is referred to as renal glycosuria. Such glycosuria may occur during pregnancy and may be caused by Fanconi syndrome, tubulointerstitial injury in the kidney.
Evaluation of glycosuria requires a 24-hour urine glucose test, with your intake of carbohydrates taken into consideration.
There are various causes for glucose in the urine. However, glycosuria is typically considered a sign of diabetes until appropriate examinations rule out this diagnosis.