Kidney Biomarker
Collection Type: Blood
Related System: Kidney
Glomerular Filtration Rate (reported as eGFR) estimates how much blood the kidneys filter each minute, normalized to body surface area (mL/min/1.73 m²). It is calculated from serum creatinine plus age, sex and sometimes race, and is the key measure used to detect and stage chronic kidney disease (CKD). Low eGFR suggests reduced kidney function; symptoms prompting testing include fatigue, swelling, reduced urine output, blood in urine or unexplained high blood pressure. eGFR normally declines with age and is influenced by muscle mass, sex, body size and certain medications; values must be interpreted in clinical context.
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Symptom Checker90-120 mL/min/1.73 m²
Q: What GFR level indicates CKD?
A: Chronic kidney disease is indicated when estimated glomerular filtration rate (eGFR) is below 60 mL/min/1.73 m² for three months or more. Stages: G1 ≥90 (normal), G2 60–89 (mild), G3a 45–59, G3b 30–44, G4 15–29, G5 <15 (kidney failure). See a clinician for diagnosis and management.
Q: Why is GFR low in CKD?
A: Glomerular filtration rate (GFR) falls in CKD because kidney damage reduces the number and function of nephrons. Scarring (glomerulosclerosis), tubulointerstitial fibrosis and loss of filtration surface lower capillary permeability. Reduced renal blood flow, increased glomerular pressure from adaptive hyperfiltration in remaining nephrons, and vascular or obstructive injury further impair filtration, leading to waste buildup and progressive decline.
Q: What is the GFR for CKD 3A and 3B?
A: Chronic kidney disease (CKD) stage 3 is split into 3A and 3B based on estimated glomerular filtration rate (eGFR). CKD 3A: eGFR 45–59 mL/min/1.73 m². CKD 3B: eGFR 30–44 mL/min/1.73 m². These reflect moderate kidney function decline and guide monitoring, medication adjustment, and referral to nephrology as needed. Management focuses on blood pressure and glucose control, plus avoiding nephrotoxins.
Q: Does GFR improve in CKD?
A: In chronic kidney disease, GFR usually declines over time and true reversal is uncommon. However, with early diagnosis and targeted treatment—blood pressure and glucose control, RAAS blockade, correcting reversible causes, and avoiding nephrotoxins—decline can be slowed and modest GFR improvement or stabilization may occur. Advanced or long-standing CKD rarely regains significant function; transplantation or dialysis are options for end-stage disease.
Q: Will drinking water increase my GFR?
A: Drinking adequate water can restore or preserve GFR if you're dehydrated—dehydration lowers GFR, and rehydration often returns it toward normal. However, extra water won’t substantially raise GFR above your kidneys’ set level, and it won’t reverse chronic kidney disease. In conditions like heart failure or hyponatremia, excess fluids can be harmful. Check with your clinician for personal advice.
Q: What is the GFR for end-stage CKD?
A: End-stage chronic kidney disease (CKD stage 5) is defined by an estimated glomerular filtration rate (eGFR) below 15 mL/min/1.73 m². Patients with eGFR in this range often require kidney replacement therapy; dialysis or transplant is commonly considered when eGFR falls to about 10–15 mL/min/1.73 m², especially if uremic symptoms or complications are present.