Urine Albumin Test (ACR): What Your Result Means
Medically Reviewed by Dr. Pedro Yelamo Vera, MD
Licensed Physician No. 484814280 · Official Medical College of Bizkaia (Spain)Last reviewed: 31 October 2026
Urine albumin test (ACR) explained: normal ranges in mg/mmol and mg/g, what raises it for a while, why it is repeated and what a lasting rise means.
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Dr. Pedro Yelamo Vera is an independent, bilingual GP licensed in Spain. Book a 15-minute video consultation in English or Spanish for €50, with a private electronic prescription issued under Spanish law when clinically appropriate.
A urine albumin test looks for a protein called albumin in your urine. Healthy kidneys keep almost all of it in the blood. A raised result can be an early sign of kidney damage, most often from diabetes or high blood pressure. One high result is not a diagnosis. It needs a repeat test before anyone calls it kidney disease.
- The test is usually reported as an albumin to creatinine ratio, or ACR. On a Spanish report it may say cociente albúmina/creatinina or microalbuminuria.
- Normal is under 3 mg/mmol in the UK, or under 30 mg/g in Spain and the US. These are two ways of writing roughly the same cut-off.
- Exercise, fever, a urine infection or a period can raise the result for a short time.
- A raised result must be confirmed on repeat samples, usually a first-morning sample.
- A lasting rise is treatable: blood pressure, blood sugar and some medicines can protect the kidneys.
Dr. Pedro Yelamo Vera is a GP licensed in Spain (Colegiado No. 484814280).
For a medical emergency, call 112 or go to the nearest local emergency department. Do not wait for a video consultation or an online reply.
What is a urine albumin test?
Albumin is the main protein in your blood. MedlinePlus explains that more than a trace in urine may be an early sign of kidney disease.
The lab measures albumin and creatinine, a waste product, in the same sample. Dividing one by the other corrects for how diluted your urine is.
In the UK it is the ACR. In the US it is often called UACR. On a Spanish report, look for cociente albúmina/creatinina, CAC or microalbuminuria.
What is a normal urine albumin level?
UK labs report ACR in mg/mmol. Spanish and US labs usually use mg/g. The three stages line up like this:
- A1, normal or mildly raised: under 3 mg/mmol, or under 30 mg/g.
- A2, moderately raised: 3 to 30 mg/mmol, or 30 to 300 mg/g.
- A3, severely raised: over 30 mg/mmol, or over 300 mg/g.
These bands come from the NHS and NICE for mg/mmol, and from the Spanish kidney consensus for mg/g. So a Spanish result of 45 mg/g and a UK result of 5 mg/mmol both sit in band A2.
"Microalbuminuria" is the older name for the A2 band, and many Spanish labs still use it. Always check the range printed next to your result.
Does one high result mean kidney disease?
No. Albumin in urine goes up and down. The Spanish kidney consensus says the diagnosis should never rest on a single test. It needs two raised results out of three samples taken over at least three months. MedlinePlus gives a similar rule: two more tests within three to six months.
In the UK, NICE asks for a repeat early-morning sample if the first ACR is between 3 and 70 mg/mmol. No repeat is needed at 70 or more, because the result is clear.
Many things raise albumin for a short time. The Spanish consensus lists fever, stress, a high-protein diet, hard exercise, a urine infection and a period. MedlinePlus adds dehydration. Doctors repeat the test once these have passed.
How do you collect the sample?
Most labs prefer the first urine of the morning. Pass a little urine into the toilet first, then fill the pot. Avoid hard exercise the day before. If you have your period or a urine infection, tell the lab: it may be better to wait.
Got an ACR or microalbuminuria result and not sure what it means?
You can book a video visit with a GP licensed in Spain, in English or Spanish. He reads your urine result with your kidney blood tests, blood pressure and medicines, and explains what to repeat and what comes next.
Who should have a urine albumin test?
Raised albumin causes no symptoms at first. MedlinePlus advises a yearly test if you have diabetes. NICE and the NHS also advise regular kidney checks with ACR and a blood test if you have:
- High blood pressure or heart disease.
- A past acute kidney injury, or kidney stones that keep coming back.
- Lupus, gout or a family history of kidney disease.
- Long-term use of medicines that can affect the kidneys, such as lithium or anti-inflammatory painkillers.
In Spain, the national consensus advises a yearly check in people at risk, and adds age over 60 and obesity.
What causes a high urine albumin?
MedlinePlus names diabetes as the commonest cause, then high blood pressure. Less common causes include immune kidney diseases and a narrowed kidney artery.
Raised albumin is not only about the kidneys. The Spanish consensus calls it a sign of damage to blood vessels across the body, linked with higher heart risk. This is why it is worth acting on.
What happens if your ACR stays high?
First, a blood test checks your eGFR, worked out from creatinine. Together, eGFR and ACR show the stage of any kidney disease. Our guide to high creatinine explains that part of the report.
Treatment aims to protect the kidneys and the heart. The NHS describes these steps:
- Blood pressure control. Medicines called ACE inhibitors or ARBs lower blood pressure and protect the kidneys. NICE advises one of them for people with kidney disease, high blood pressure and an ACR over 30 mg/mmol.
- Blood sugar control if you have diabetes. The NHS notes that dapagliflozin, an SGLT2 inhibitor, is often used for people with kidney disease and diabetes. It is not right for everyone.
- A statin to lower heart and stroke risk.
- Lifestyle: stop smoking, keep salt under 6 g a day and avoid ibuprofen-type painkillers unless a doctor says they are safe.
Most people are followed by their GP. NICE advises a kidney specialist for an ACR of 70 mg/mmol or more, unless diabetes explains it and is already well treated. It also advises referral for an ACR over 30 with blood in the urine. In Spain, the consensus sets the referral line at over 300 mg/g.
What about children and pregnancy?
Children are tested only when there is a reason, such as diabetes. NICE advises a specialist for a child whose ACR is 3 mg/mmol or more on a repeat early-morning sample.
In pregnancy, your midwife checks your urine and blood pressure at every visit. The NHS explains that this looks for pre-eclampsia, which usually appears after 20 weeks. Contact your maternity unit or go to urgencias today if you are pregnant and have a severe headache, blurred vision or flashing lights, pain below the ribs, or sudden swelling of your face, hands or feet.
Talking it through with a doctor by video
Dr. Yelamo is a GP licensed in Spain. He sees adults, children and pregnant patients by video, every day from 07:30 to 20:30 (Spain time). In the visit he will:
- Read your urine result with your eGFR, creatinine, HbA1c and blood pressure.
- Check whether something such as exercise, fever or an infection could have raised it.
- Explain when and how to repeat the test.
- Tell you whether you need treatment, closer checks or a specialist.
He does not promise any test or prescription before the visit. Where clinically appropriate, following a genuine evaluation. Treatment and prescriptions are issued solely at the doctor's discretion based on evidence-based clinical guidelines.
A prescription is never guaranteed: it is issued only where clinically appropriate after a genuine evaluation, as a private electronic prescription under Spanish law. This service is for urgent, non-emergency care. In an emergency, call 112.
See how the Urgent Care video visit works. It lasts 15 minutes and costs €50.
This guide is general information. It does not replace a consultation with your doctor.
Frequently asked questions
What is a normal urine albumin test result?
Under 3 mg/mmol in the UK, or under 30 mg/g in Spain and the US. These are roughly the same cut-off written in different units.
Is microalbuminuria the same as kidney disease?
Not on one test. A raised result must be confirmed on repeat samples over about three months. If it stays raised, it counts as a sign of kidney damage.
Can exercise affect a urine albumin test?
Yes. Hard exercise, fever, a urine infection or a period can raise albumin for a short time. Avoid hard exercise the day before.
What does an ACR of 5 mg/mmol mean?
It is in the moderately raised band, A2. Your doctor will repeat it on an early-morning sample and check your eGFR and blood pressure.
What is cociente albúmina/creatinina on a Spanish report?
It is the Spanish name for the albumin to creatinine ratio, the ACR. It is usually given in mg/g.
Sources
- NICE NG203: Chronic kidney disease, assessment and management
- NHS: Chronic kidney disease, diagnosis
- NHS: Chronic kidney disease, treatment
- MedlinePlus: Microalbumin creatinine ratio
- MedlinePlus: Microalbuminuria test
- García-Maset et al., Nefrología: Spanish consensus on chronic kidney disease
Related guides
Medical Citations & Sources
This content is written and reviewed by a licensed physician with reference to the following official health authorities.
