TABLE 2

Defining the severity of chronic kidney disease

Stage	GFR, mL/min/1.73 m₂		Descriptor
G1	≥ 90		Normal or high
G2	60–89		Mildly decreased^a
G3a	45–59		Mildly to moderately decreased
G3b	30–44		Moderately to severely decreased
G4	15–29		Severely decreased
G5	< 15		Kidney failure
Albuminuria	AER, mg/day	ACR, mg/g	Descriptor

A1	< 30	< 30	Normal to mildly increased
A2	30–300	30–300	Moderately increased^b
A3	> 300	> 300	Severely increased

↵a In the absence of evidence of kidney damage, neither GFR category G1 nor G2 meets the criteria for chronic kidney disease.
↵b Includes the nephrotic syndrome (AER usually > 2,200 mg/day).
ACR = albumin-creatinine ratio equivalent; AER = albumin excretion rate; GFR = glomerular filtration rate
Reprinted from Kidney International Supplements, 3:19–62, KDIGO. Chapter 1: definition and classification of CKD, copyright 2013, doi:10.1038/kisup.2012.64, with permission from Elsevier.