24-hour urine collection

Some urine tests require the collection of all the urine produced over a certain amount of time (usually 24 hours). This test will show how much urine your kidneys produce in one day. Creatinine clearance, for instance, is determined by a 24-hour urine collection test and a blood test.

Residual renal function

When you first start dialysis your own kidneys may still work, but not well enough to keep you healthy. The amount of residual renal function (RRF) varies from patient to patient.

The longer a patient keeps some RRF, the healthier they will be. Over time, it is likely the RRF will decline. In many kidney failure patients it eventually disappears. As the RRF declines, the dialysis prescription will be adjusted to compensate for the reduced function. Creatinine clearance testing is used to assess RRF.

Urinalysis

A small sample of urine can be analyzed for abnormalities such as blood or protein, or to detect if an infection is present.