Kidney disease stages, explained

What counts as chronic kidney disease

The international KDIGO guideline defines chronic kidney disease (CKD) as a problem with kidney structure or function that lasts more than 3 months, such as an eGFR below 60 or albumin in the urine (KDIGO 2024). The 3 month rule matters: one low result can be a short dip, so a stage is only given once the change has lasted.

CKD is staged by its cause, its GFR category and its albuminuria category (KDIGO 2024). Most lab reports and doctors talk about the last two, which this page explains.

The G stages: eGFR

eGFR (estimated glomerular filtration rate) describes how well the kidneys filter blood. It is calculated from a creatinine blood test, age and sex; you can work yours out with our eGFR calculator. KDIGO uses six GFR categories (KDIGO 2024):

NIDDK, part of the US National Institutes of Health, puts it more simply: an eGFR of 60 or more is in the normal range, less than 60 may mean kidney disease, and 15 or less is called kidney failure (NIDDK).

The A categories: urine albumin

Healthy kidneys keep albumin, a protein, in the blood. When the filters are damaged, some leaks into the urine. The test is the urine albumin-to-creatinine ratio (UACR or ACR). KDIGO uses three categories (KDIGO 2024):

Labs outside the US often report ACR in mg/mmol. There the same lines are 3 and 30 mg/mmol (KDIGO 2024). NIDDK lists 30 mg/g or less as normal and more than 30 mg/g as a possible sign of kidney disease (NIDDK).

Putting the two together: the risk chart

KDIGO combines the G stage and the A category into one chart that shows the outlook, meaning the risk of kidney disease getting worse and of related problems such as heart disease (KDIGO 2024). Find your eGFR row and your albumin column:

Two things stand out. First, albumin changes the risk a lot: someone with a normal eGFR but an ACR over 300 is in a higher risk box than someone with an eGFR of 50 and no albumin. Second, the low risk boxes for G1 and G2 with A1 are not CKD at all unless there is some other sign of kidney damage (KDIGO 2024).

A risk box describes groups of people. It does not say what will happen to any one person, and it does not decide treatment. That is for your doctor, who also looks at the cause and how your numbers change over time.

What stage 3 kidney disease means

Stage 3 is where many people first hear the words kidney disease on a lab report. It covers an eGFR of 30 to 59 that has lasted more than 3 months, split into G3a (45 to 59) and G3b (30 to 44) (KDIGO 2024). On the chart, G3a without albumin is moderate risk, and the risk rises with albumin and as eGFR falls into G3b (KDIGO 2024).

Who has CKD and who should be tested

CDC estimates that 14% of US adults, about 37 million people, have CKD, and that about 9 in 10 adults with it do not know (CDC). It is more common with age: 34% of people 65 or older, compared with 13% of people aged 45 to 64 and 6% aged 18 to 44 (CDC). It is also more common in non-Hispanic Black adults (22%) than in non-Hispanic White (13%) or Hispanic adults (12%) (CDC).

The most common causes in adults are diabetes and high blood pressure (NIDDK). CDC estimates that about 38% of adults with diabetes have CKD (CDC). NIDDK recommends getting checked if you have diabetes, high blood pressure, heart disease or a family history of kidney failure, every year if you have diabetes, and asking your provider how often otherwise (NIDDK). A check means both tests, the eGFR blood test and the urine albumin test (NIDDK).

Common questions

What are the 5 stages of kidney disease?

The stages people usually mean are the eGFR stages G1 to G5, with stage 3 split into 3a and 3b, so there are six categories in all (KDIGO 2024). Doctors add the albumin category (A1 to A3), so a full stage reads like "G3a A2".

Is an eGFR of 55 stage 3?

An eGFR of 55 falls in the G3a range (45 to 59). It is called stage 3 CKD only if it has stayed below 60 for more than 3 months (KDIGO 2024). One result is a reason to repeat the test, not a diagnosis.

Can you have kidney disease with a normal eGFR?

Yes. Albumin in the urine for more than 3 months counts as CKD even when eGFR is 60 or higher (KDIGO 2024). That is why the urine test matters.

Can kidney disease stages go back down?

eGFR can move up or down between tests, and what happens over time depends on the cause. That is a question for your doctor. This page does not give treatment advice.

Work out your eGFR or see which numbers to ask your doctor for.