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Albumin-to-Creatinine Ratio
The albumin-to-creatinine ratio (ACR) measures protein leaking into the urine, an early sign of kidney damage, especially in diabetes and high blood pressure.
Quick answer
Albumin-to-Creatinine Ratio: what it is and what the results mean
The ACR is a urine test that compares the amount of a protein called albumin with creatinine. Small amounts of albumin in the urine can be an early marker of kidney damage before other tests become abnormal.
- Why it is done: It is used to screen for and monitor kidney disease, particularly in people with diabetes or high blood pressure, and to help decide on treatment to protect the kidneys and reduce cardiovascular risk.
- Understanding results: A raised ACR suggests protein leaking through the kidneys, which can be an early sign of kidney damage.
What it is
The ACR is a urine test that compares the amount of a protein called albumin with creatinine. Small amounts of albumin in the urine can be an early marker of kidney damage before other tests become abnormal.
Why it is done
It is used to screen for and monitor kidney disease, particularly in people with diabetes or high blood pressure, and to help decide on treatment to protect the kidneys and reduce cardiovascular risk.
What to expect
You provide a urine sample, ideally the first one of the morning, in a pot. No special preparation is needed, though vigorous exercise beforehand can temporarily raise the result.
Understanding the results
A raised ACR suggests protein leaking through the kidneys, which can be an early sign of kidney damage. A single raised result is often repeated to confirm, and higher levels prompt closer monitoring and treatment.
Good to know
Risks and limitations
It is a simple, safe test. Results can be temporarily affected by exercise, infection, menstruation and fever, so an abnormal result is usually confirmed with a repeat sample.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Albumin-to-Creatinine Ratio: frequently asked questions
Why is an early morning sample preferred?
The first urine of the morning is more concentrated and less affected by daytime activity, giving a more reliable measure of albumin leaking through the kidneys.
What does a raised ACR mean if I have diabetes?
It can be an early sign of diabetic kidney damage. Finding it early allows treatment to protect the kidneys, so people with diabetes are checked regularly.
Related tests
Other other investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Association for Laboratory Medicine / relevant professional body
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