Stages and labs
Stage 3 CKD (3a vs 3b) Explained
This article is general information. Your nephrologist or renal dietitian knows your lab results and can tell you what is right for you.
Stage 3 is the middle of the five stages of chronic kidney disease (CKD). It is divided into two parts, 3a and 3b. The National Kidney Foundation (NKF) notes that stages 3a and 3b are when most people with CKD are first diagnosed. This article is general information only.
The numbers behind 3a and 3b
- Stage 3a: an eGFR between 45 and 59 for 3 months or more, described by the NKF as a mild to moderate loss of kidney function.
- Stage 3b: an eGFR between 30 and 44, described as a moderate to severe loss of kidney function.
The NKF says the eGFR has to be confirmed with repeat testing over time, to rule out a sudden, short-term kidney problem known as acute kidney injury. It also recommends a urine albumin test (uACR) for a fuller picture. For how eGFR works, see What Is eGFR?
Symptoms at stage 3
The NKF says people at stage 3a typically have no symptoms. When symptoms do appear, the NKF mentions tiredness, nausea and a weaker appetite, weight loss that has no clear reason, dry or itchy skin, and a change in how often you pass urine. Many of these have other causes, which is why they are not a reliable way to tell the stage.
Possible complications
According to the NKF, complications such as anemia, mineral and bone disorder and metabolic acidosis (a build-up of acid in the blood) become possible as kidney function falls. For stage 3a it describes the risk as very low, but still recommends screening with simple blood tests. The NKF also says that people with stage 3 CKD are at higher risk of high blood pressure, and that heart disease risk is higher even when the urine albumin result is below 30.
Conditions that often go along with stage 3
The NKF lists high blood pressure, diabetes, high cholesterol and heart disease as common related conditions. Managing them is a large part of kidney care. Read more in High Blood Pressure, Diabetes and Your Kidneys.
What care generally involves
For stage 3a, the NKF describes four general areas, which your care team will adapt to you.
Daily habits. Staying away from tobacco, starting gently with short walks and building up, getting enough sleep, keeping stress in check and, if your healthcare team advises it, losing a little weight.
Eating. The NKF mentions keeping sodium under 2300 mg a day when there is high blood pressure, and says potassium, phosphorus or calcium may be adjusted according to blood tests. A kidney dietitian can help you with this. Our overview Kidney-Friendly Eating Basics covers the main ideas.
Medicines. Which medicines are used depends on the person, and the doses of other medicines may need a second look because some can build up when the kidneys work less well. The NKF says anti-inflammatory pain relievers known as NSAIDs should generally be avoided. Ask your doctor or pharmacist before taking any over-the-counter medicine.
Follow-up. Regular blood pressure checks and repeat eGFR and uACR tests.
The NKF’s patient guide on first steps after a diagnosis suggests seeing a nephrologist (kidney specialist) when the eGFR falls below 30. Your doctor may suggest a referral earlier, and that is a decision for you and your doctor.
To prepare for appointments, see Questions to Ask Your Nephrologist.
Related reading
Sources
- National Kidney Foundation: Stage G3a Chronic Kidney Disease (CKD), updated July 17, 2026
- National Kidney Foundation: Estimated Glomerular Filtration Rate (eGFR), updated February 5, 2026
- National Kidney Foundation: First Steps After Diagnosis of CKD
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