The protein-to-creatinine ratio in urine allows doctors to determine how much protein is in urine at a specific moment in time, according to Lab Tests Online. A high ratio implies protein's presence, while a low ratio may indicate that the body is not excreting a significant amount of protein.
Properly functioning kidneys do not allow measurable amounts of protein to filter into urine, reports WebMD, though Lab Tests Online points out that trace amounts are normal and can vary throughout the day or because of activity. A 24-hour urine sample measures how much protein is excreted through urine over a full day, and the test can distinguish between occasional and consistent levels. However, consistent and significant amounts of protein in urine are an early warning sign of kidney disease. The condition, known as proteinuria, is associated with bladder cancer, diabetes, hypertension, urinary tract infections and kidney infections. Proteinuria can also be caused by medications that affect the kidneys.
If progressive kidney damage is causing proteinuria, doctors may prescribe medications to control or prevent the damage from worsening, states WebMD. Exercising while limiting salt and fat intake can help, according to the American Kidney Fund. People with diabetes or high blood pressure face increased risk of proteinuria damaging the kidneys.