What is CKD?
Chronic kidney disease is defined as abnormalities of kidney structure or function, present for more than 3 months, with implications for health.
Two things must both be true:
- The duration criterion is met (>3 months)
- There is at least one of the following:
-
- evidence of decreased kidney function — an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73m²
OR - a marker of kidney damage — albuminuria (albumin-creatinine ratio (ACR) ≥3 mg/mmol), haematuria (of kidney origin), imaging abnormality, or biopsy finding
- evidence of decreased kidney function — an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73m²
Why duration matters: A single low eGFR reading could reflect an acute kidney injury (AKI). CKD requires persistence. If a patient has no prior blood tests, you need repeat measurements across at least 90 days before diagnosing CKD.