Kidney Function Tests (eGFR & Creatinine)
Kidney function tests measure how well your kidneys filter waste, using blood creatinine and the eGFR — a calculation of your filtration rate.
Plain English
Patient-Friendly Explanation
Kidney function tests are blood tests that check how well your kidneys are filtering waste products. The main marker is creatinine, a waste product from muscle that the kidneys remove; because normal levels depend on muscle mass, creatinine is then used to calculate the eGFR (estimated glomerular filtration rate), which expresses kidney function as a percentage of normal. Healthy kidneys filter at roughly 90 or above on this scale. Kidney function matters in weight management because obesity raises the risk of chronic kidney disease, and the results guide the safe use of many medications, including some diabetes and weight-loss treatments that are adjusted or avoided when filtration is reduced.
Medical
Clinical Definition
The estimated glomerular filtration rate (eGFR) is derived from serum creatinine using equations such as CKD-EPI, with results expressed in mL/min/1.73m2 and used to stage chronic kidney disease (G1: >=90 through G5: <15). Serum creatinine alone is an imperfect measure of filtration because it varies with muscle mass, age, sex and diet, and this is particularly relevant in obesity where high lean mass can mask declining function; cystatin C-based estimates offer an alternative when muscle-mass effects are suspected. In weight management, baseline renal function assessment is prudent before starting medications with renal clearance or nephrotoxic potential, informs dosing of glucose-lowering drugs, and supports monitoring in patients with diabetes, hypertension or after bariatric surgery, where dehydration or malabsorption can transiently affect kidney function.
Key Insight
Why It Matters
Kidney function is easy to overlook in a weight consultation because it rarely causes symptoms until it is quite reduced. Our standard screening blood panel includes creatinine and eGFR so that we catch any kidney concerns early and choose treatments that are safe for your kidneys.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: September 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
