What Is Microalbumin Creatinine Ratio?

Microalbumin creatinine ratio, often called urine albumin-to-creatinine ratio or ACR, is a urine test that checks for small amounts of albumin protein in your urine. It can provide useful information about kidney health, especially for people with diabetes, high blood pressure or other risk factors for kidney disease.

Healthy kidneys usually keep most albumin in the blood. If the kidney filters are under strain or damaged, small amounts of albumin may leak into the urine. A microalbumin creatinine ratio test may help detect this early, before obvious symptoms develop.

What is microalbumin creatinine ratio?

Microalbumin creatinine ratio is a urine test that compares the amount of albumin with the amount of creatinine in your urine.

Albumin is a protein normally found in the blood. Creatinine is a waste product produced by muscles and passed out in urine. By comparing albumin with creatinine, the test adjusts for how concentrated or diluted your urine is.

This makes the result more useful than measuring urine albumin alone.

What does the ACR test measure?

The ACR test measures whether there is more albumin in the urine than expected. Small amounts of albumin in the urine may be described as microalbuminuria.

A raised ACR may suggest that the kidneys are allowing albumin to leak into the urine. This should be interpreted alongside your symptoms, medical history, blood pressure and blood kidney function results.

Why is the ACR test important?

The ACR test is important because kidney problems can develop silently. Many people do not notice symptoms in the early stages of kidney disease.

A urine ACR test may help assess early kidney changes, particularly in people with:

• Diabetes
• High blood pressure
• Known chronic kidney disease
• Cardiovascular disease
• A family history of kidney disease
• Previous abnormal urine or kidney function results

ACR is often considered alongside blood kidney function tests, such as creatinine and estimated glomerular filtration rate, also known as eGFR.

What does a high microalbumin creatinine ratio mean?

A high microalbumin creatinine ratio means there is more albumin in your urine than expected. This may suggest that the kidney filters are under strain or not working as well as they should.

However, a single high ACR result does not always mean you have kidney disease. Results can sometimes be temporarily raised and may need to be repeated.

Your healthcare professional will interpret your result based on your overall health, risk factors and any other test results.

Who should consider a urine ACR test?

A urine ACR test may be useful if you are at higher risk of kidney disease or if your clinician wants to check for protein leakage in the urine.

You may be advised to have an ACR test if you have:

• Type 1 or type 2 diabetes
• High blood pressure
• Known kidney disease
• Heart or blood vessel disease
• A family history of kidney disease
• Protein detected on a urine dipstick test
• Previous abnormal eGFR or creatinine results

It may also be used as part of a broader kidney health assessment or health check, depending on your symptoms and risk factors.

How is the microalbumin creatinine ratio test done?

The microalbumin creatinine ratio test is usually done using a urine sample. An early morning urine sample may sometimes be preferred because it can give a more consistent result.

1. You provide a urine sample.
2. The laboratory measures albumin and creatinine in the sample.
3. The result is calculated as an albumin-to-creatinine ratio.
4. Your result is reviewed alongside your health background and other tests.

No blood sample is needed for the ACR test itself, although blood tests are often used alongside urine testing to assess kidney function more fully.

What can affect ACR results?

Several factors can affect ACR results. A raised result may be linked to kidney disease, but it can also be influenced by temporary factors.

Possible factors include:

• Recent strenuous exercise
• Urinary tract infection
• Fever or recent illness
• Dehydration
• Menstruation or sample contamination
• Poorly controlled diabetes
• High blood pressure

If your result is unexpectedly high, repeat testing may be recommended before any firm conclusions are made.

What happens if your ACR is high?

If your ACR is high, your healthcare professional may recommend repeating the test to confirm whether the finding is persistent. They may also review other markers of kidney and general health.

This may include:

• Blood kidney function tests, such as creatinine and eGFR
• Blood pressure measurement
• Diabetes testing or diabetes control review
• Medication review
• Assessment for urinary infection
• Follow-up monitoring or referral where appropriate

A high ACR result should not be ignored, but it should be interpreted carefully rather than viewed as a diagnosis on its own.

When should you seek medical advice?

You should speak to a healthcare professional if you have a high ACR result, persistent protein in the urine, diabetes, high blood pressure or known kidney disease.

Seek urgent medical advice if you have:

• Blood in your urine
• New swelling of the face, legs or ankles
• Severe shortness of breath
• Very reduced urination
• Severe pain in your side or back
• Chest pain, confusion or feeling very unwell
• Symptoms of very high blood pressure, such as severe headache or visual changes

If symptoms are severe or sudden, contact NHS 111, your GP urgently or call 999 in an emergency.

Frequently Asked Questions

Take a proactive approach to kidney health

Microalbumin creatinine ratio is a simple urine test that can support early assessment of kidney health. It is especially useful when interpreted alongside blood kidney function tests, blood pressure, diabetes status and your wider medical history.

If you are concerned about kidney health, urine test results, diabetes or blood pressure, consider speaking with a healthcare professional about the most appropriate tests for your situation.