What can distort a creatinine-based estimate
Creatinine comes from muscle, so anything that changes muscle mass or creatinine handling shifts the estimate. Bodybuilders and people taking creatine read falsely low; people with low muscle mass, including many older adults, read falsely high.
- • Cystatin C-based eGFR is the tiebreaker when creatinine is unreliable.
- • Albuminuria stages (A1–A3) matter as much as GFR for prognosis.
- • Several common medications need dose adjustment below eGFR 30–50.
FAQ
What is a normal GFR?
Above 90 mL/min/1.73m² is considered normal, though values decline naturally with age. Sustained values below 60 define chronic kidney disease.
Does the CKD-EPI 2021 equation still use race?
No. The 2021 revision removed the Black-race coefficient and is now the standard recommended equation in US laboratories.
Can eGFR improve?
Yes, if the cause is reversible — dehydration, medication effects, or an acute injury. Established structural kidney damage generally does not reverse, but progression can be slowed.
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