Chronic Kidney Disease: What You Need to Know

What is CKD?

Your kidneys clean waste and extra fluid out of the blood, help control blood pressure, keep salts such as sodium and potassium in balance, and make hormones that help produce red blood cells and keep bones healthy.

KDIGO (Kidney Disease: Improving Global Outcomes), the international guideline group for kidney care, defines CKD as abnormalities of kidney structure or function that are present for more than three months and affect health. In practice, a doctor usually looks for one or both of these, confirmed over time:

• an eGFR below 60 mL/min/1.73m², meaning the kidneys are filtering less than expected, or
• albumin in the urine at a urine ACR of 3 mg/mmol (30 mg/g) or more, a sign that the kidney filters are leaking.

Other signs, such as certain changes on a kidney scan or in a urine test, can also count. The three-month rule matters because kidney results can dip for a short time, for example during dehydration, a serious infection or with some medicines. A sudden drop in kidney function is called acute kidney injury. It is a different problem and is managed differently.

What causes CKD?

Diabetes and high blood pressure are the two most common causes of CKD worldwide. Other causes include:

• glomerulonephritis, which means inflammation of the kidney's filters
• inherited conditions, such as polycystic kidney disease
• long-term blockage of urine flow, for example from kidney stones or an enlarged prostate
• repeated kidney infections
• some infections that affect the whole body, such as HIV or hepatitis B and C
• regular long-term use of some medicines, including some anti-inflammatory painkillers

Sometimes no single cause is found. Where possible, knowing the cause helps a doctor plan care.

CKD and high blood pressure

High blood pressure (often called presha) can damage the small blood vessels in the kidneys over many years. Kidney disease can also raise blood pressure, because damaged kidneys hold on to more salt and water. Each problem can make the other worse. Read more in high blood pressure and your kidneys.

CKD and diabetes

High blood sugar over time can harm the kidney's filters. The earliest sign is usually albumin in the urine, found with a urine ACR test. This is why people with diabetes are usually advised to have their kidneys checked at least once a year. See diabetes and kidney health.

CKD stages

KDIGO describes CKD using two measurements together:

• G categories (G1 to G5), based on eGFR. G1 is 90 or above and G5 is below 15 mL/min/1.73m².
• A categories (A1 to A3), based on urine ACR. A1 is below 3 mg/mmol (30 mg/g) and A3 is above 30 mg/mmol (300 mg/g).

A result may be written as, for example, "G3a A2". The combination gives a better picture of future risk than either number alone. Only a clinician can stage CKD, using repeated tests over time. The full tables are on the CKD stages page.

Kidney function tests

The main blood test is creatinine, a waste product from the muscles that healthy kidneys remove. On its own, creatinine is not enough to judge the kidneys, because it also depends on muscle mass, age, sex and diet. So labs use a validated equation to turn the creatinine result into an eGFR, an estimate of how well the kidneys filter. Creatinine reference ranges vary between labs, so always use the range printed on your own report.

Doctors sometimes add a blood test called cystatin C when the creatinine-based eGFR may be less reliable. Other tests that may be used include urinalysis (a general urine test) and a kidney ultrasound scan. See kidney function tests and the creatinine test.

Albuminuria: albumin in the urine

Albumin is a protein that should stay in the blood. When the kidney filters are damaged, some albumin leaks into the urine. This is called albuminuria. It is measured with a urine ACR test, which compares albumin with creatinine in the same urine sample.

Albuminuria is important for two reasons. It can be one of the earliest signs of kidney damage, and higher levels are linked with a higher risk of kidney disease getting worse and of heart problems. ACR can rise for a short time after hard exercise, during a fever or infection, or during menstruation, so a raised result is usually repeated before any conclusion is drawn.

Monitoring kidney function

CKD is followed over time. Doctors look at the trend in eGFR and ACR across several tests, not one result on its own. How often tests are repeated depends on the stage, the cause and other health conditions. Keeping copies of your results helps any doctor you see. Read monitoring CKD.

Managing risk

For many people, CKD changes slowly, and finding it early gives time to reduce risk. The details are always individual, but care commonly includes:

• keeping blood pressure within the range agreed with your doctor
• keeping blood sugar under control if you have diabetes
• reviewing all medicines with a clinician, including over-the-counter painkillers and herbal remedies
• not smoking, staying active, and following food and fluid advice from a doctor or dietitian
• regular tests to watch for change

Doctors may also discuss medicines that can help protect the kidneys and heart in some people with CKD. Whether any of these are suitable depends on your results and history. Please do not start, stop or change any medicine without speaking to your doctor.

When specialist care may be appropriate

Many people with early CKD are cared for by a general doctor or physician. Guidelines such as KDIGO 2024 and NICE NG203 describe situations where referral to a nephrologist (kidney specialist) is often considered. Examples include a low eGFR (for example below 30), a high level of albumin in the urine, kidney function that is falling quickly, blood pressure that stays high despite several medicines, or a cause that is unclear or may be inherited. Your doctor will decide what applies to you. Read when to see a nephrologist.

Finding kidney care in Mombasa

Most people in Mombasa first get kidney results from a laboratory or a hospital outpatient clinic, then bring them to a doctor. If you have been told you have CKD, or your results suggest it, the next step is usually a review with a doctor who can look at your eGFR and ACR together and plan follow-up. Our pages on CKD care in Mombasa and what happens at a kidney consultation can help you prepare. If you would like help finding a verified provider on Mombasa Island, in Nyali, Bamburi, Likoni, Changamwe or elsewhere, use find kidney care.

Frequently asked questions

Is a high creatinine result the same as CKD?

No. Creatinine is one blood test. Doctors turn it into an eGFR and look at it together with a urine ACR test, over more than three months, before CKD can be diagnosed. A single high result can have other causes, such as dehydration or some medicines.

What are the early symptoms of CKD?

Early CKD usually causes no symptoms at all. Swelling, tiredness or changes in urine tend to appear later, if at all, and have many other causes. Blood and urine tests are the way CKD is found.

Does everyone with CKD end up needing dialysis?

No. Many people with CKD never reach kidney failure. The risk depends on eGFR, the level of albumin in the urine, the cause and other health conditions, which is why doctors look at these together and follow them over time.

Can CKD be cured?

CKD is usually a long-term condition. Some causes can be treated, and for many people the aim of care is to slow or prevent further change and to lower the risk of heart problems. A doctor can explain what is realistic in your situation.

This page explains what a test or condition involves. It is not a diagnosis and does not replace advice from a doctor who knows your history. Your results should be interpreted together with your symptoms, other tests and a clinical assessment. Medical disclaimer.