By the time a person reaches ESRD, his or her kidneys are doing little to clean the blood of wastes and regulate the body's fluid and chemical balance. Dialysis is an alternative for performing these functions in place of the failing kidneys. It cannot cure kidney failure, but it can prolong life by preventing the build-up of waste products in the body. Dialysis is generally started when a person's kidney function is down to about 10 percent of normal levels.
Healthcare providers use several tests to monitor a person's kidney function.
These include both blood and urine tests. One blood test looks at levels of serum creatinine, a chemical the body produces as it digests proteins. Normally, creatinine is excreted by the kidneys, but kidney failure causes it to accumulate in the blood. A urine test can determine how much creatinine is being filtered out and excreted by the kidneys. When serum creatinine is high and urine creatinine is low, a person's kidney function is decreasing.