Chronic renal failure (chronic renal insufficiency) is divided into 5 stages according to the CKD staging in the United States. According to chronic kidney disease (CKD), it is divided into stages 1, 2, 3, 4 and 5. The staging criteria are based on the degree of impairment of the glomerular filtration rate, and the glomerular filtration rate (GFR) is calculated based on the creatinine value of the kidney function and the weight for age. The staging values can be recorded as 90%, 60%, 30% and 15% staging criteria. The specific staging is as follows: CKD1 stage: normal or elevated GFR with renal damage. gfr ≥ 90% CKD2 stage: mild GFR decline with renal damage. gfr: 60% to 89% CKD3 stage: moderate GFR decline. gfr: 30% to 59% CKD4 stage: severe GFR decline. gfr: 15% to 29% CKD5 stage: renal failure. gfr <15%< span=""> or dialysis.