eGFR is a derived laboratory estimate of glomerular filtration rate (GFR), the volume of plasma filtered by the kidneys per unit time. The value is calculated from serum creatinine plus demographic factors; some equations include a race-specific coefficient historically applied for individuals identified as African American. Common clinical formulas include MDRD and CKD-EPI, developed from population data to approximate measured GFR without direct clearance testing. Biologically, eGFR reflects renal filtration of small solutes and is a central measure of how kidneys contribute to homeostasis. The race coefficient was introduced to reconcile creatinine-based estimates with measured GFR in certain study cohorts; its use and interpretation have been revisited to ensure appropriate and equitable assessment across populations.

Lower eGFR values indicate reduced estimated filtering capacity and are associated with slower clearance of metabolic waste, altered fluid and electrolyte balance, and links to markers of cardiovascular strain. Higher eGFR values generally indicate greater estimated filtration and can reflect normal individual variation, increased renal blood flow, early hyperfiltration patterns, or analytic and biological influences such as muscle mass differences. eGFR should be interpreted together with creatinine, urine findings, blood pressure, metabolic labs, and the full Cardio Zoomer profile to understand patterns rather than to assert a standalone diagnosis.

Cardio Zoomer includes eGFR (African American) to place kidney filtration within a systems-level cardiovascular assessment. It helps clinicians see how renal filtering capacity interacts with metabolic load, fluid status, medication handling, and cardiovascular biomarkers. As part of the integrated panel, eGFR supports pattern recognition that informs personalized risk stratification and clinical interpretation.