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A urine albumin-creatinine ratio, often abbreviated uACR or ACR, is a urine test used to check whether albumin protein is leaking into the urine. It is one of the most useful early tests for kidney damage, especially in people with diabetes, high blood pressure, heart disease, or a family history of kidney disease.
The short answer: a high urine albumin-creatinine ratio usually means there is more albumin in the urine than expected. This can happen when the kidney filters are under stress or damaged, but it can also be temporarily raised by exercise, fever, urinary tract infection, menstrual blood contamination, high blood sugar, or a sudden blood pressure spike. A low urine albumin-creatinine ratio is usually not a problem; in most lab reports, “low” simply means little or no albumin was detected.
Quick take
- Typical normal uACR: less than 30 mg/g.
- Moderately increased: 30 to 299 mg/g, sometimes historically called “microalbuminuria.”
- Severely increased: 300 mg/g or higher, sometimes historically called “macroalbuminuria.”
- One high result does not always diagnose chronic kidney disease. Results often need to be repeated, especially if the value is mildly or moderately elevated.
- uACR should be interpreted with eGFR, blood pressure, diabetes status, urinalysis findings, medications, and your health history.
What the urine albumin-creatinine ratio measures
Albumin is a protein normally found in the blood. Healthy kidneys keep most albumin in the bloodstream and allow only very small amounts to pass into urine. When the filtering units of the kidneys are irritated or damaged, albumin can leak into the urine. This is called albuminuria, a form of protein in the urine.
Creatinine is a waste product from normal muscle metabolism. It is expected to appear in urine because the kidneys filter it out of the blood. The uACR test measures both urine albumin and urine creatinine, then reports the ratio between them. Using the ratio is helpful because urine concentration changes throughout the day depending on hydration. A very diluted urine sample may have low albumin concentration even if the daily albumin loss is meaningful; a very concentrated sample may look more abnormal. The ratio corrects for some of that variation.
The National Kidney Foundation describes uACR as an important test for identifying kidney damage, along with estimated glomerular filtration rate, or eGFR. The National Institute of Diabetes and Digestive and Kidney Diseases also notes that urine albumin measurement is used to help diagnose kidney disease and monitor progression.
High, normal, and low urine albumin-creatinine ratio ranges
Most U.S. labs report uACR in milligrams of albumin per gram of creatinine, written as mg/g. Some labs, especially outside the U.S., use mg/mmol. Always read the unit on your report before comparing results.
| uACR result | Common category | What it generally means |
|---|---|---|
| <30 mg/g | Normal to mildly increased | Little or no excess albumin detected. This is usually the target range. |
| 30–299 mg/g | Moderately increased albuminuria | More albumin than expected. May suggest early kidney damage or increased kidney and cardiovascular risk if persistent. |
| ≥300 mg/g | Severely increased albuminuria | A more significant albumin leak. Needs prompt clinical follow-up, especially if persistent or accompanied by abnormal eGFR, blood, casts, swelling, or high blood pressure. |
These categories are consistent with the albuminuria categories used in KDIGO chronic kidney disease guidance and summarized in patient-facing materials from kidney organizations. The categories are useful, but they are not the whole story. A result of 32 mg/g and a result of 280 mg/g are both in the “moderately increased” category, yet they may carry different levels of concern depending on whether they persist and what the rest of the kidney evaluation shows.
What a high urine albumin-creatinine ratio can mean
A high uACR means the urine contains more albumin relative to creatinine than expected. The most important question is whether the finding is temporary or persistent.
If the elevation persists on repeat testing, it may indicate kidney filter damage. In adults, persistent albuminuria is one marker used in the diagnosis and staging of chronic kidney disease. The National Kidney Foundation defines chronic kidney disease as abnormalities of kidney structure or function present for more than three months, with albuminuria of ACR 30 mg/g or higher listed as one marker of kidney damage.
Common medical contexts associated with a high uACR include:
- Diabetes. Diabetes is a leading cause of kidney disease. The American Diabetes Association’s 2026 Standards of Care in Diabetes recommend assessing kidney function with random uACR and eGFR at least annually in people with type 1 diabetes for five years or longer and in all people with type 2 diabetes.
- High blood pressure. High pressure in blood vessels can damage kidney filters over time, and kidney disease can also worsen blood pressure control.
- Heart and blood vessel disease. Albuminuria is associated with higher cardiovascular risk, so clinicians often view uACR as a kidney and vascular risk marker, not just a urine number.
- Glomerular diseases. These are conditions that affect the kidney’s filtering units, such as certain immune or inflammatory kidney diseases.
- Medication or toxin-related kidney injury. Some drugs or exposures can affect kidney function, particularly in people with existing risk factors. Do not stop prescribed medicine without speaking with a clinician.
- Acute illness or kidney injury. A sudden illness, dehydration, infection, or hospitalization can sometimes raise kidney markers temporarily.
A high uACR can occur even when the blood kidney function number, eGFR, is still normal. That is one reason uACR is valuable: albuminuria may appear before a major drop in eGFR. Conversely, a person can have reduced eGFR with little albumin in the urine, so both tests are needed for a fuller picture.
How concerning is a mildly high uACR?
A mildly high result, such as just above 30 mg/g, should be taken seriously but not interpreted in isolation. Many clinicians repeat the test, often using a first-morning urine sample, and review possible temporary causes. If two of three samples over several months are abnormal, the result is more likely to represent persistent albuminuria rather than day-to-day variation.
A value in the hundreds, especially 300 mg/g or higher, usually deserves more urgent follow-up. If the result is very high, rapidly rising, or paired with a falling eGFR, blood in the urine, swelling, uncontrolled blood pressure, or abnormal urine sediment, clinicians may consider additional testing or referral to a kidney specialist.
What a low urine albumin-creatinine ratio can mean
For this test, a low result is usually good news. Because the goal is to have very little albumin in the urine, a low uACR generally means there is no significant albumin leak at the time of testing.
Some reports do not provide an exact ratio if the albumin is below the assay’s detection limit. You may see wording such as “unable to calculate,” “below analytical range,” “less than,” or “albumin too low to calculate ratio.” In many cases, this is not a bad result. It can mean the urine albumin concentration was so low that the lab could not calculate a meaningful ratio. The interpretation depends on the report’s reference range and any comments from the laboratory.
A low uACR does not rule out every kidney problem. uACR is best at detecting albumin leakage, especially from glomerular kidney disease and diabetes-related kidney changes. Some kidney or urinary tract conditions may cause reduced eGFR, blood in the urine, electrolyte abnormalities, kidney stones, structural abnormalities, or non-albumin proteins without much albuminuria. If your clinician is concerned about kidney health, they may also order eGFR, urinalysis with microscopy, urine protein-creatinine ratio, kidney imaging, or other tests.
Temporary or false high uACR results
Albumin excretion can vary substantially from sample to sample. That is why a single abnormal result—especially a mild or moderate one—often leads to repeat testing rather than an immediate diagnosis.
The National Kidney Foundation advises avoiding intense exercise for 24 hours before a uACR test because it can temporarily raise the result. It also lists fever, infection, heart failure flare, urinary tract infection, urinary or menstrual bleeding, and sudden dramatic increases in blood pressure or blood sugar as factors that may interfere with the test. A Quest Diagnostics clinical FAQ similarly notes that urinary tract infection, menstrual bleeding, fever, congestive heart failure, marked hyperglycemia, and marked hypertension may elevate urinary albumin excretion.
| Situation | Why it matters | Typical practical step |
|---|---|---|
| Hard workout within 24 hours | Can temporarily increase albumin in urine | Ask whether to repeat after avoiding strenuous exercise |
| Fever or acute infection | Inflammation and illness can raise albumin excretion | Repeat when recovered, if clinically appropriate |
| UTI symptoms | Infection and urine inflammation can affect the result | Discuss urinalysis, culture, treatment, and retesting |
| Menstrual or urinary bleeding | Blood can contaminate the sample and raise protein readings | Repeat when bleeding has resolved, unless urgent evaluation is needed |
| Very high blood sugar or blood pressure | Can temporarily stress kidney filters | Address the acute issue and repeat based on clinician guidance |
How to prepare for a repeat uACR test
Preparation instructions vary by lab and ordering clinician, but these steps often help make the sample more interpretable:
- Ask whether a first-morning urine sample is preferred. KDIGO notes that the collection method should remain consistent and preferably use a first-morning void specimen for ACR monitoring.
- Avoid intense exercise for 24 hours before the sample unless your clinician tells you otherwise.
- Tell the ordering clinician if you have UTI symptoms, fever, a recent illness, visible blood in urine, menstrual bleeding, or a major blood sugar or blood pressure spike.
- Follow clean-catch instructions carefully. This usually means washing hands, cleaning the genital area, starting to urinate into the toilet, then collecting the midstream urine in the cup.
- Use the timing your clinician requested. Random spot urine is common, but some situations call for first-morning, timed, or 24-hour urine collection.
What to do after a high uACR result
Your next step depends on the degree of elevation, whether it is new or persistent, and your overall kidney risk. In general, it is reasonable to ask your clinician these questions:
- Was my result reported in mg/g or another unit?
- Was the result mildly, moderately, or severely elevated?
- Should I repeat the test, and should the repeat be a first-morning urine sample?
- Do I need an eGFR blood test, urinalysis, urine microscopy, or urine culture?
- Could exercise, infection, menstruation, blood pressure, or blood sugar have affected the result?
- How should we monitor this over time?
- Should my blood pressure, diabetes plan, kidney-protective medications, or cardiovascular risk plan be adjusted?
- Do I need a nephrology referral?
If albuminuria is persistent, treatment often focuses on reducing kidney and cardiovascular risk. Depending on the person, that may include optimizing blood pressure, improving diabetes management, stopping smoking, reducing sodium intake, reviewing medicines that can affect the kidneys, managing cholesterol, and considering kidney-protective medications. NIDDK notes that albuminuria may be reduced with blood pressure medicines called ACE inhibitors or ARBs in appropriate patients, and with nutrition planning such as reducing sodium and using the right amount and type of protein.
Do not start or stop medications based only on a lab number. For example, ACE inhibitors, ARBs, SGLT2 inhibitors, mineralocorticoid receptor antagonists, diuretics, and anti-inflammatory pain relievers can all matter in kidney care, but the right choice depends on eGFR, potassium, blood pressure, diabetes status, pregnancy considerations, other medicines, and the reason for albuminuria.
When to seek prompt medical advice
Contact a clinician promptly if a high uACR is accompanied by any of the following:
- New swelling in the legs, face, or around the eyes
- Foamy urine that is persistent or worsening
- Visible blood in the urine
- Severe or suddenly worsening high blood pressure
- Shortness of breath, chest pain, confusion, or severe weakness
- Reduced urination, dehydration, or recent serious illness
- A rapidly rising uACR or falling eGFR
These symptoms do not prove kidney disease, but they can indicate a situation that should not wait for routine follow-up.
Cost and access considerations
Urine albumin-creatinine ratio testing is commonly ordered in primary care, endocrinology, cardiology, and nephrology settings. It may be covered by insurance when medically indicated, especially for diabetes, hypertension, chronic kidney disease monitoring, or cardiovascular risk assessment. Out-of-pocket costs vary widely depending on insurance, deductible status, ordering pathway, and whether the test is bundled with other kidney labs such as eGFR, basic metabolic panel, urinalysis, or a kidney profile.
If you are paying cash or using a consumer lab ordering service, compare the effective total cost, not just the advertised test price. The total can include the uACR test price, clinician or ordering-provider fee, specimen collection fee, lab processing fee, membership or platform fee, and any follow-up visit cost if you need interpretation. Also check whether the service is available in your state, whether the sample is collected at a walk-in lab or at home, how results are delivered, and whether abnormal results receive clinician review.
At-home or point-of-care albumin screening may be convenient, but positive or borderline results are commonly confirmed with a quantitative laboratory uACR. For medical decision-making, especially if a result may lead to a chronic kidney disease diagnosis or medication change, a lab-based quantitative ratio is typically more useful than a color-change strip alone.
How uACR fits with other kidney tests
uACR is not the same as eGFR. The two tests answer different questions:
| Test | Sample | Main question it answers |
|---|---|---|
| uACR | Urine | Is albumin leaking into the urine? |
| Serum creatinine with eGFR | Blood | How well are the kidneys filtering blood? |
| Urinalysis | Urine | Are there signs such as blood, protein, glucose, ketones, nitrites, leukocytes, or casts? |
| Urine protein-creatinine ratio | Urine | How much total protein is in the urine, including albumin and non-albumin proteins? |
A person can have normal eGFR and high uACR, low eGFR and normal uACR, or abnormalities in both. That combination helps clinicians estimate kidney risk, monitor progression, and decide when additional evaluation is needed.
FAQs about high and low urine albumin-creatinine ratio
Is a high urine albumin-creatinine ratio always kidney disease?
No. A high result can be caused by kidney damage, but it can also be temporary. Exercise, fever, infection, urinary tract infection, menstrual or urinary bleeding, heart failure flare, sudden high blood pressure, and marked high blood sugar can raise uACR. Persistent elevation over time is more concerning than a single isolated abnormal result.
What is considered a dangerously high uACR?
There is no single “danger” cutoff that applies to everyone, but 300 mg/g or higher is generally considered severely increased albuminuria and should be followed up promptly. Very high, rapidly rising, or persistent results are more concerning, especially if eGFR is falling or urinalysis shows blood or casts.
Can dehydration cause a high uACR?
Hydration affects urine concentration, which is one reason the albumin-creatinine ratio is used instead of albumin concentration alone. The ratio corrects for some concentration differences, but illness, dehydration, and other stressors can still affect results. Ask whether repeat testing is appropriate if your sample was collected during dehydration or acute illness.
Does a low uACR mean my kidneys are perfect?
Not necessarily. A low or normal uACR is reassuring for albumin leakage, but it does not evaluate every aspect of kidney health. eGFR, blood pressure, urinalysis, imaging, and medical history may still matter.
Why is my urine albumin high but my albumin-creatinine ratio normal?
Urine albumin concentration can look high or low depending on how concentrated the urine is. The ratio compares albumin with creatinine to adjust for urine concentration. For interpretation, focus on the line that says albumin/creatinine ratio, ACR, uACR, or alb/creat ratio.
How often should uACR be checked?
People with diabetes are commonly checked at least annually, and people with known chronic kidney disease may be monitored more often depending on stage and risk. Your clinician may recommend repeat testing sooner after a new abnormal result.
Can uACR improve?
Yes, uACR can decrease, especially when a temporary cause resolves or when kidney risk factors are better controlled. In people with persistent albuminuria, lower or stable albumin levels may suggest that treatment is helping, but interpretation depends on the full clinical picture.
Sources
- National Kidney Foundation: Urine albumin-creatinine ratio (uACR)
- NIDDK: Albuminuria, albumin in the urine
- CDC: Testing for chronic kidney disease
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
- American Diabetes Association: Chronic Kidney Disease and Risk Management, Standards of Care in Diabetes—2026
- Quest Diagnostics clinical FAQ: Albumin, random urine with creatinine
Educational note
This article is for general education and does not diagnose kidney disease or replace care from a licensed clinician. Lab interpretation depends on your result, units, repeat testing, symptoms, medical history, medications, and other kidney tests such as eGFR and urinalysis.
