eGFR Creatinine-Cystatin C Calculation With Albumin:Creatinine-Protein:Creatinine Ratios, Urine

This panel checks how well your kidneys are filtering waste from your blood and whether they are leaking protein into your urine, which they normally should not do. Two blood proteins—creatinine and cystatin C—are used together to give a more accurate estimate of your kidney filtering rate (eGFR) than either one alone. The urine tests measure albumin and total protein, which can signal early kidney damage even before you feel any symptoms. Together, these results help your doctor determine the health of your kidneys, track any changes over time, and decide if additional evaluation or treatment adjustments are needed. Staying well-hydrated, managing blood pressure and blood sugar, and avoiding nephrotoxic medications are general kidney-health principles, but your doctor will guide any specific recommendations based on your results.

When elevated: Elevated uACR or uPCR with reduced eGFR indicates established CKD with glomerular damage, conferring substantially increased risk for CKD progression to end-stage kidney disease, cardiovascular morbidity, and mortality; higher albuminuria categories independently predict adverse outcomes even with preserved eGFR. When low: A low or undetectable uACR/uPCR combined with a normal or high eGFR is generally reassuring and consistent with preserved kidney function; however, very high eGFR values (>120 mL/min/1.73m²) may occasionally reflect hyperfiltration states (e.g., early diabetic nephropathy, pregnancy, or single-kidney hypertrophy) warranting clinical context.

This panel is most relevant to endurance athletes and those undertaking intense training, as heavy exercise can temporarily elevate creatinine and proteinuria due to increased muscle breakdown and renal perfusion stress. Monitoring eGFR trends and urine protein helps distinguish normal exercise-induced changes from early kidney injury, while the dual-biomarker approach (creatinine + cystatin C) is particularly useful for muscular athletes whose higher muscle mass can skew creatinine-only estimates. For most recreational athletes with stable training, routine kidney screening is lower priority unless there's a history of dehydration, NSAIDs use, or family kidney disease.