Diagnosis

Chronic kidney disease (CKD) can be diagnosedwith blood and urine tests.

In many cases, it's only picked up because a routine blood or urine test indicates that the kidneys may not beworkingnormally.

This page covers:

Who shouldbe tested

Tests

Test results and CKD stages

Who shouldbe tested for CKD?

See your GP if you have persistent symptoms of CKD . They can look for other possible causes and arrange tests if necessary.

But askidney diseaseoften has no symptoms in the early stages, some people at a higher risk should ideally be tested regularly.

Regular testingis recommended for people with:

• high blood pressure
• diabetes
• acute kidney injury sudden damage to the kidneys that causes them tostop workingproperly
• cardiovascular disease conditions that affect the heart, arteries and veins, such as coronary heart disease or heart failure
• other conditions that can affect the kidneys such as kidney stones , an enlarged prostate or lupus
• a family history of advanced CKD or an inherited kidney disease
• protein or blood in their urine where there's no known cause

People taking long-term medications that can affect the kidneys, such as lithium,omeprazoleor non-steroidal anti-inflammatory drugs (NSAIDs) , should also be tested regularly.

Talk to your GP if you think you may need regular testing for kidney disease.

Tests for CKD

Blood test

The main test forkidney diseaseis a blood test that's used to work out how well your kidneys are working. The test measures the levels of a waste product called creatinine in your blood.

Using this result,a calculation that takes into account your age, gender and ethnic group is then done to work out howmany millilitresof waste your kidneys are able to filter in a minute.

This measurement is known as your estimatedglomerular filtration rate (eGFR).

Healthy kidneys should be able to filter more than 90ml/min. You may have kidney disease if your result is lower than this.

below.

Urine tests

Urine tests are also usually carried out to:

• check the levels of substances calledalbumin and creatinine in your urine known as thealbumin:creatinine ratio, or ACR
• check for blood or protein in your urine

AlongsideyoureGFR measurement, these testscan help give a more accuratepicture of how well your kidneys are working.

Read about test results , below, for more information.

Other tests

Sometimesother tests are also used to assess the level of damage to your kidneys.

These may include:

• an ultrasound scan , magnetic resonance imaging (MRI) scan or computerised tomography (CT) scan tosee what the kidneys look like and check whether there are any blockages
• a kidney biopsy a small sample of kidney tissue is removed using a needleso the cells can be examined under a microscope for signs of damage

Test results and stages of CKD

Yourtest results can be used to determine how damaged your kidneys are, known as the stage of CKD.

This can help your doctor decide the best treatment for you and determine how often you should have tests to monitor your condition.

Your eGFR resultisgivenas a stagefrom one to five:

• stage 1 (G1) a normaleGFR (above 90ml/min), but other tests have detected signs of kidney damage
• stage2 (G2) a slightly reducedeGFR (60-89ml/min),with other signs of kidney damage
• stage3a (G3a) an eGFRof 45-59ml/min
• stage 3b(G3b) an eGFRof 30-44ml/min
• stage4(G4) an eGFR of 15-29ml/min
• stage5 (G5) an eGFR below 15ml/min, meaning thekidneys have lost almost all of their function

Your ACR result is given as a stage from one to three:

• A1 an ACR of less than 3mg/mmol
• A2 an ACR of 3-30mg/mmol
• A3 an ACR of more than 30mg/mmol

For both eGFR and ACR,ahigherstage indicates more severe kidney disease.

Want to know more?

• Advice for new kidney patients
• Kidney Research UK: stages of kidney disease
• The Renal Association: CKD stages