Serum creatinine level (with optional 24-hour urine collection for creatinine clearance calculation)

Why This Test Matters for Dialysis Patients

When you restart dialysis, your doctor may check your creatinine level to ensure your kidneys are no longer filtering waste properly. This helps adjust your dialysis schedule and prevent buildup of harmful substances in your blood.

How the Test Works

Your blood is drawn to measure creatinine, a waste product naturally produced from muscle use. If your kidneys aren’t working well, creatinine builds up in your blood. Some labs may also analyze a 24-hour urine sample to calculate how well your kidneys filter waste over time.

What to Expect Before the Test

No special preparation is needed, but tell your lab about any recent illness, dehydration, or changes in diet (like high-protein foods). Avoid strenuous activity 24 hours before the test.

What the Results Mean

Higher-than-normal creatinine levels may indicate poor kidney function or fluid overload. Your doctor will compare results with your baseline (before dialysis) to monitor progress. If creatinine is too high, adjustments to dialysis timing or fluid intake may be needed.