According to the K／DOQI Guidlines constituted by National Kidney Foundation (NKF) in 2002, Chronic Kidney Disease (CKD) can be classified into five stages, which is quite significant for the treatment. The stages are measured by kidney functions instead of specific diagnosis, so Glomerular Filtration Rate (GFR) is the most helpful measurement for this classification, and it refers to how well the kidney filter the blood.
Kidney damage with normal or ↑GFR
Kidney damage with mild ↓GFR
＜15 (or Dialysis)
Chronic Kidney Disease is defined as either kidney damage or GFR＜60mL/min/1.73m2 for ≥ 3months. Kidney damage is defined as pathologic abnormalities or markers of damage, including abnormalities in blood or urine tests or imaging studies. )