Medically reviewed by Dr. Griffin M, MBBS, MS (General Surgery), MCh (Urology). Specialist in Urology, Andrology & Kidney Transplant Surgery | Last reviewed: October 2026
The kidneys play an important role in maintaining overall health. They filter waste products and excess water from the blood, help regulate blood pressure, maintain the balance of minerals and electrolytes, and support the production of red blood cells. When the kidneys become damaged and gradually lose their ability to perform these functions, a condition known as chronic kidney disease (CKD) can develop.
Chronic kidney disease may progress slowly over several months or years. In its early stages, a person may feel completely healthy because the kidneys can continue performing many of their functions despite some damage. As the condition progresses, symptoms and complications may become more noticeable.
Understanding the stages of chronic kidney disease helps patients and families understand test results, recognise possible changes in health, and discuss appropriate care with their healthcare team. Although CKD can become serious, its progression varies from person to person. Regular monitoring and suitable medical management can help protect remaining kidney function and address associated health problems.
What Is Chronic Kidney Disease?
Chronic kidney disease is a long-term condition in which the kidneys show persistent damage or a reduced ability to filter blood. It is generally diagnosed when evidence of kidney damage or reduced kidney function continues for at least three months.
Common causes include diabetes, high blood pressure, certain inflammatory kidney conditions, inherited disorders, and other medical problems that affect the kidneys. Some people develop CKD without noticeable symptoms, making medical assessment particularly important for those with known risk factors.
Doctors assess kidney health using blood and urine tests, medical history, and, when appropriate, imaging investigations. The results help determine the extent of kidney damage and the likelihood of further progression.
How Are the Stages of Chronic Kidney Disease Determined?
The five main stages of chronic kidney disease are classified largely according to the estimated glomerular filtration rate (eGFR). This measurement estimates how effectively the kidneys filter waste from the blood. It is calculated using a blood creatinine result and other patient information.
A lower eGFR generally indicates reduced kidney function. However, doctors do not determine the severity of CKD from a single test result alone. They also consider urine albumin levels, changes in kidney function over time, the underlying cause, other health conditions, and the person’s overall health.
The five stages are:
- Stage 1: eGFR of 90 or higher, with evidence of kidney damage.
- Stage 2: eGFR between 60 and 89, with evidence of kidney damage.
- Stage 3a: eGFR between 45 and 59.
- Stage 3b: eGFR between 30 and 44.
- Stage 4: eGFR between 15 and 29.
- Stage 5: eGFR below 15, indicating severely reduced kidney function.
These values are expressed in millilitres per minute per 1.73 square metres of body surface area (mL/min/1.73 m²). Stage 3 is divided into two categories, so the classification includes five main stages but six eGFR categories.
Stage 1 Chronic Kidney Disease: Early Kidney Damage
Stage 1 CKD is the earliest stage. At this point, the eGFR is 90 or higher, which is generally within the normal or high range. However, there must be other evidence of kidney damage for the condition to be classified as CKD.
Possible findings include albumin in the urine, certain structural abnormalities of the kidneys, or other persistent signs of kidney damage.
Symptoms of Stage 1 CKD
Most people do not experience noticeable symptoms during this stage. Kidney function may appear normal on routine blood tests, even when urine tests reveal signs of damage.
For this reason, people with diabetes, high blood pressure, or a family history of kidney disease may benefit from appropriate kidney health assessments recommended by their doctor.
Management of Stage 1 CKD
Management focuses on identifying the underlying cause and reducing the risk of further damage. Depending on individual needs, this may include controlling blood pressure and blood glucose, following a balanced diet, remaining physically active, avoiding smoking, and attending scheduled medical reviews.
Doctors may recommend repeat blood and urine tests to monitor kidney function and albumin levels. Medicines may also be prescribed according to the person’s condition.
Stage 2 Chronic Kidney Disease: Mildly Reduced Kidney Function
In Stage 2 CKD, the eGFR is between 60 and 89. Kidney function is mildly reduced, but this result alone does not establish chronic kidney disease. Evidence of kidney damage must also be present.
Some people remain without symptoms for years. Others may have an underlying condition that requires regular monitoring.
Signs and Assessment
Stage 2 CKD is often identified through routine investigations rather than symptoms. Urine albumin testing can help identify damage that may not be apparent from the eGFR alone.
A doctor may review blood pressure, blood glucose, medication use, previous test results, and any history of kidney-related problems.
Managing Stage 2 CKD
Treatment depends on the cause of kidney damage and the person’s overall health. It may involve managing diabetes or high blood pressure, reviewing medicines that could affect the kidneys, maintaining healthy lifestyle habits, and repeating tests at intervals recommended by the healthcare team.
Early identification gives patients and doctors an opportunity to address risk factors before more substantial loss of kidney function occurs.
Stage 3 Chronic Kidney Disease: Moderately Reduced Kidney Function
Stage 3 CKD indicates a moderate reduction in kidney function. It is divided into Stage 3a and Stage 3b because the degree of reduction differs between these categories.
Stage 3a CKD
Stage 3a is associated with an eGFR between 45 and 59. Some people continue to feel well, while others may develop symptoms or laboratory abnormalities.
Possible problems include tiredness, anaemia, changes in mineral balance, and an increased risk of cardiovascular disease. These findings are not specific to CKD and require appropriate assessment.
Stage 3b CKD
Stage 3b is associated with an eGFR between 30 and 44. Kidney function is more reduced than in Stage 3a, and the risk of certain complications may be higher.
Depending on the individual, symptoms may include persistent fatigue, swelling in the feet or ankles, changes in urination, reduced appetite, or muscle cramps. Some people still experience few noticeable symptoms.
Management of Stage 3 CKD
Medical management generally focuses on monitoring kidney function, controlling the underlying cause, and detecting complications early. A doctor may assess blood pressure, urine albumin, blood count, potassium, bicarbonate, and other measurements when clinically appropriate.
A nephrologist may be involved depending on the patient’s risk of progression, test results, complications, and local referral guidance.
Dietary recommendations should be individualised. Restricting potassium, phosphorus, protein, or fluids is not necessary for every person with Stage 3 CKD. Changes should be based on medical advice and relevant test results.
Stage 4 Chronic Kidney Disease: Severely Reduced Kidney Function
Stage 4 CKD occurs when the eGFR falls between 15 and 29. At this stage, the kidneys have significantly reduced filtering capacity, and complications become more likely.
Some people develop fluid retention, persistent tiredness, nausea, poor appetite, itching, or changes in their usual urination pattern. Others may have few symptoms despite substantial loss of kidney function.
Possible Complications of Stage 4 CKD
The kidneys help regulate several important processes in the body. When their function declines, complications may include:
- Anaemia: Reduced kidney function can affect the production of erythropoietin, a hormone involved in red blood cell production.
- Fluid retention: Excess fluid may cause swelling and contribute to high blood pressure or breathing difficulties.
- Electrolyte imbalance: Potassium and other mineral levels may become abnormal.
- Bone and mineral disorders: Changes in calcium, phosphorus, and vitamin D metabolism may affect bone health.
- Metabolic acidosis: The body may have difficulty maintaining its normal acid-base balance.
Not everyone develops all these complications. Regular testing helps doctors identify and manage problems according to individual needs.
Management of Stage 4 CKD
Care usually involves closer monitoring, treatment of associated conditions, and discussions about future treatment options if kidney function continues to decline. A healthcare team may review medicines, nutritional needs, blood pressure, blood glucose, and cardiovascular risk.
For some patients, preparation for dialysis or kidney transplantation may be appropriate. Planning ahead allows time to understand the available options and make informed decisions. However, reaching Stage 4 does not mean that every person will immediately require dialysis or a transplant.
Stage 5 Chronic Kidney Disease: Kidney Failure
Stage 5 CKD is also called kidney failure. It is associated with an eGFR below 15, although the need for treatment is determined by the person’s symptoms, complications, test results, and overall clinical condition.
At this stage, the kidneys may no longer remove enough waste and excess fluid to maintain the body’s normal balance.
Symptoms of Stage 5 CKD
Possible symptoms include severe tiredness, nausea, vomiting, reduced appetite, persistent itching, swelling, muscle cramps, difficulty concentrating, and shortness of breath. Some people experience changes in urination, while others may continue to pass urine.
Symptoms vary considerably, and they cannot reliably determine the stage of kidney disease without medical investigations.
Treatment Options for Stage 5 CKD
Treatment is individualised and may include dialysis, kidney transplantation for eligible patients, or comprehensive supportive care depending on clinical needs and personal preferences.
- Dialysis helps remove waste products and excess fluid when the kidneys cannot perform these functions adequately. Haemodialysis filters blood through a dialysis machine, while peritoneal dialysis uses the lining of the abdomen as part of the filtering process.
- Kidney transplantation involves placing a suitable donor kidney into a recipient. It may be an option for eligible patients after a detailed assessment.
Some people may choose a supportive approach that focuses on symptom management and quality of life without dialysis. Decisions should be made through discussions with the treating team, taking into account medical circumstances and the patient’s preferences.
What Tests Help Diagnose and Monitor CKD?
Doctors use more than one investigation to assess chronic kidney disease. Common tests include:
1. Blood Creatinine and eGFR
Creatinine is a waste product measured in the blood. The eGFR is calculated using creatinine and other relevant information to estimate kidney filtering capacity. Repeated results help show whether kidney function is stable or changing.
2. Urine Albumin-to-Creatinine Ratio
Albumin is a protein that may appear in urine when the kidneys’ filtering structures are damaged. The urine albumin-to-creatinine ratio (UACR) helps measure the amount of albumin relative to creatinine in a urine sample.
3. Blood Pressure Measurement
High blood pressure can contribute to kidney damage and may also develop as kidney function declines. Regular measurement helps guide treatment.
4. Additional Blood Tests
Depending on the stage and clinical situation, doctors may check blood count, potassium, bicarbonate, calcium, phosphorus, and other indicators of complications.
5. Imaging Investigations
An ultrasound or other imaging investigation may be recommended to examine kidney size, structure, obstruction, or other abnormalities when indicated.
The choice and frequency of tests depend on the person’s condition and the treating doctor’s assessment.
Lifestyle and Daily Care for People With CKD
Daily habits can support overall health and form part of a kidney care plan. Recommendations should be adapted to the stage of CKD, other medical conditions, laboratory results, and nutritional requirements.
- Follow a balanced diet: Choose foods according to your healthcare team’s advice. Salt, protein, potassium, and phosphorus needs differ between individuals.
- Monitor blood pressure and blood glucose: Keep recommended appointments and follow the treatment plan.
- Stay physically active: Choose an activity that suits your fitness level and medical condition.
- Avoid smoking: Smoking can increase cardiovascular risk and may contribute to poorer health outcomes.
- Take medicines as prescribed: Discuss over-the-counter medicines, herbal products, and supplements with a healthcare professional before use.
- Attend regular reviews: Blood and urine tests help monitor changes even when you feel well.
- Ask about fluid intake: Drinking extra water does not reverse CKD, and some people need an individual fluid plan.
Patients should seek prompt medical assessment for new or worsening symptoms. Severe breathlessness, chest pain, confusion, or a marked reduction in urine output accompanied by feeling unwell may require urgent medical attention.
Conclusion
The stages of chronic kidney disease describe the extent of kidney damage and the reduction in kidney filtering capacity. From early-stage changes to kidney failure, each stage provides information that helps guide monitoring and medical care. However, the stage alone does not determine how a person will feel or how quickly the condition may progress.
Blood and urine tests, regular follow-up, management of underlying conditions, and individualised treatment are important parts of CKD care. If you have diabetes, high blood pressure, a family history of kidney disease, or abnormal kidney test results, discuss appropriate assessment and monitoring with your healthcare professional.
Understanding your test results and attending recommended reviews can help you take an informed role in managing kidney health.
Read also Tests to Check Your Kidney Health.
