Urine Albumin-to-Creatinine Ratio: Why People With Diabetes Get This Test

The urine albumin-to-creatinine ratio (UACR) test checks for small amounts of albumin, a blood protein, leaking into your urine. People with diabetes get it because high blood sugar can damage the kidney's tiny filters, and leaking albumin can be an early sign of that damage, often before you feel anything. This article explains how the test works, how to read a result, what can raise it, and when symptoms need urgent care.

What the urine albumin-to-creatinine ratio test measures

Albumin is a protein that normally stays in your blood. Healthy kidney filters hold most of it back, so only a very small amount reaches the urine. Creatinine is a waste product from muscle that the kidneys release into urine at a fairly steady pace through the day.

A UACR test measures both substances in the same urine sample and compares them. Dividing albumin by creatinine corrects for how dilute or concentrated the sample is. That is why a single small cup of urine can be used instead of a full day of collection. According to MedlinePlus (NIH) on kidney tests, an albumin-to-creatinine ratio is one of the urine tests used to look for kidney damage.

You may also see the result described as "microalbumin" or "urine ACR." These terms are often used for the same family of tests. Your lab report will show the number, the unit, and a reference range.

Why people with diabetes are tested for albumin in the urine

Over years, high blood sugar and related factors such as high blood pressure can injure the small blood vessels in the kidneys. This is called diabetic kidney disease. Several factors contribute, and the mechanism is not fully understood. Early kidney damage often causes no pain, no change in how urine looks, and no obvious symptoms.

Albumin in the urine can be one of the earliest measurable signs. That is the reason diabetes care teams commonly pair a urine albumin test with a blood test that estimates kidney filtering. If you want to understand the blood side of the picture, our articles on high creatinine and on low eGFR cover those numbers. This page focuses on the urine test.

The test is relevant to both type 1 and type 2 diabetes. You can read more about each in the MedlinePlus pages on type 1 diabetes and type 2 diabetes. Your clinician decides how often you need the test based on your type of diabetes, how long you have had it, your other conditions, and your earlier results.

Albumin in urine is also linked to heart health

The UACR is not only a kidney number. A multicenter retrospective study of people with coronary artery disease, published through PubMed Central (NIH), found that a higher urine albumin-to-creatinine ratio was associated with higher cardiovascular mortality, both in people with and without type 2 diabetes. An association in a retrospective study does not show cause, but it helps explain why clinicians treat a rising UACR as a reason to look at the whole cardiovascular picture, including blood pressure and cholesterol.

A separate cross-sectional study, also on PubMed Central (NIH), examined how kidney function related to diabetic retinopathy (eye damage) in people with type 2 diabetes. Findings like this are one reason eye exams and kidney tests are often scheduled as part of the same diabetes care plan.

How the test is done and how to prepare

The test uses a urine sample, often a "spot" sample collected at the clinic or a lab. Some clinics ask for a first-morning sample. There is no needle and no fasting is usually needed, though you should follow any instructions your lab gives you.

• Wash your hands and follow the cleaning steps on the collection kit.
• Collect a "midstream" sample, which means starting to urinate, then catching the middle part in the cup.
• Tell the clinic about recent strenuous exercise, fever, a urinary tract infection, or your menstrual period. These can affect the result.
• Bring or list your medications and supplements so the care team can interpret the number in context.

Reading your UACR result

Your lab report lists a reference range and flags results above it. Results are generally reported as milligrams of albumin per gram of creatinine (mg/g). Clinicians commonly sort results into categories such as normal to mildly increased, moderately increased, and severely increased albumin in the urine. The exact cutoffs and category names come from kidney disease guidelines, so use the range printed on your own report and ask your clinician how it applies to you.

A few points are helpful when you look at your result:

• One result is a snapshot. Albumin levels can vary from day to day. Clinicians usually want to see a high result repeated on separate occasions over several months before they consider it persistent.
• The number is read with other tests. Clinicians combine your history, blood pressure, a blood-based kidney filtering estimate (eGFR), and the urine result.
• Higher is not an emergency by itself. A high UACR with no symptoms is usually handled with a prompt appointment, not a trip to the emergency room.

Other things that can raise urine albumin

Diabetes is one common reason, but it is not the only one. Several other situations can cause a temporary or lasting rise:

• Urinary tract infection or other urinary tract irritation
• Fever or acute illness
• Vigorous exercise shortly before the test
• Menstrual blood in the sample
• Poorly controlled high blood pressure
• Heart failure or other conditions that affect the kidneys
• Other kidney conditions that are not related to diabetes

Because of this, a high result is a prompt to look further, not a diagnosis. If you have a known cause such as a recent infection, your clinician may simply repeat the test later.

What usually happens after a high result

Next steps are individual, but the usual approach combines repeat testing and treating the factors that may be driving kidney strain. Your clinician may discuss:

• Repeat UACR testing to see whether the result is persistent.
• Blood tests such as creatinine and eGFR to estimate how well the kidneys are filtering.
• Blood pressure review. Blood pressure control is a major part of protecting the kidneys.
• Blood sugar review. Your A1C trend and daily glucose patterns help guide diabetes treatment. See our article on A1C and glucose tolerance testing for how diabetes is diagnosed.
• Medication review. Some medicines used in diabetes and kidney care, such as ACE inhibitors, angiotensin receptor blockers (ARBs), and SGLT2 inhibitors, are chosen in some people with albumin in the urine. Whether one is appropriate for you is a prescriber's decision.

Medication cautions matter here. ACE inhibitors and ARBs carry a boxed warning on their labels about harm to a developing baby if taken during pregnancy, so tell your prescriber if you are pregnant, planning a pregnancy, or might become pregnant. These medicines can also raise potassium levels and can strain the kidneys during dehydration, so kidney function and potassium are often checked after starting them. An ACE inhibitor and an ARB are generally not combined, so tell your prescriber and pharmacist about every blood pressure medicine you take. They can also cause angioedema, which is swelling of the lips, tongue, face, or throat, and that needs emergency care.

SGLT2 inhibitors can cause ketoacidosis, sometimes even when blood sugar is not very high. Nausea, vomiting, abdominal pain, unusual tiredness, or fast breathing in someone taking one needs urgent evaluation, even if a glucose reading looks normal. These medicines can also cause genital yeast infections and fluid loss. Rarely, a serious infection of the genital or perineal area (Fournier gangrene) has been reported, with severe pain, swelling, or redness and often fever. Ask your prescriber or pharmacist for "sick-day" guidance, meaning what to do with these medicines during vomiting, diarrhea, poor fluid intake, or before surgery, since clinicians sometimes advise pausing them in those situations. Do not change the dose or timing of any prescription on your own.

Also tell your clinician before using over-the-counter pain relievers such as ibuprofen or naproxen regularly. These NSAIDs can affect the kidneys in some people, and your clinician can tell you whether they are appropriate for you.

Day-to-day habits that support kidney health

Lifestyle steps can support the treatment your clinician recommends, not replace it. Many people discuss these with their care team:

• Keeping blood sugar within the range your clinician sets for you
• Checking blood pressure at home if your clinician recommends it, and continuing any monitoring they have asked for
• Limiting sodium, since high salt intake can raise blood pressure
• Not smoking, which is linked to faster kidney and blood vessel damage
• Staying physically active as your health allows
• Attending scheduled eye, foot, and kidney checks

The MedlinePlus pages on diabetes offer general patient information on managing the condition.

Signs that kidney or diabetes trouble needs attention

Early albumin leakage usually causes no symptoms. As kidney function declines, or if a diabetes emergency develops, signs can appear. Swelling in the legs, ankles, feet, or around the eyes may suggest the body is holding extra fluid. Fluid can also build up in the lungs and cause shortness of breath, especially when lying flat. Foamy urine, tiredness, poor appetite, and nausea can occur with kidney problems, though they also have many other causes.

Severe symptoms can point to a medical emergency. Chest pain, severe trouble breathing, confusion, fainting, or a seizure need emergency care. Swelling of the lips, tongue, face, or throat, or trouble swallowing or breathing, can be angioedema from an ACE inhibitor or ARB and also needs 911. In someone with kidney disease, a racing, irregular, or very slow heartbeat or sudden severe muscle weakness can reflect high potassium and needs emergency care. Sudden face drooping, arm weakness, or speech difficulty are stroke signs, and diabetes and kidney disease can raise stroke risk, so these also call for 911 first. Repeated vomiting with extreme thirst, confusion, or drowsiness in a person with diabetes can reflect dangerously high blood sugar or another diabetes emergency, including ketoacidosis, and needs emergency care. In someone taking an SGLT2 inhibitor, nausea, vomiting, abdominal pain, or fast breathing can signal ketoacidosis even with a normal glucose reading. Severe pain, swelling, or redness of the genital or perineal area with fever, in someone taking an SGLT2 inhibitor, can signal a rare but serious infection and also needs emergency care.

Other changes should be reported to a clinician on the same day or next available appointment, as listed in the box below.

When to Seek Medical Care