Urine test: uACR (urine albumin-to-creatinine ratio)

What is the uACR test?

The urine albumin-to-creatinine ratio (uACR) is a urine test used to detect early kidney damage. This test measures the amount of albumin in the urine, a protein that is in the blood compared to creatinine in the urine. This is also referred to as albuminuria or proteinuria.

Albumin is a type of protein usually in the blood that helps transport nutrients. Its presence in your urine can be a sign of kidney damage. Creatinine is a waste product filtered out of the blood by the kidneys. By measuring the ratio of albumin to creatinine, the uACR test will give your doctor an overview of your kidney health and detect chronic kidney disease (CKD) early. 

Why is it important to get a uACR test? 

While other tests, like the eGFR test, assess kidney function based on blood creatinine levels, the uACR test looks at protein levels in urine, helping detect early kidney damage. Creatinine levels can be affected by a person's muscle mass — people with lower muscle mass may have an eGFR that overestimates their kidney function, while those with higher muscle mass may have an eGFR that underestimates it. Because the uACR test is not influenced by muscle mass, it helps provide a fuller picture of kidney health and damage.

The uACR test can also help you and your doctor understand how likely your kidney disease may get worse and lead to kidney failure. A higher uACR number can mean your kidney disease is more likely to progress without proper management. The higher the number, the more likely your kidney disease will advance to kidney failure. This makes the uACR test an important tool for understanding and addressing kidney disease early and for assessing the severity of kidney damage.

How often should I get tested?

If you have diabetes, high blood pressure, or a family history of kidney disease you may be at a higher risk of developing chronic kidney disease (CKD). For people at a high risk for CKD, it's recommended that your healthcare provider test your kidney health with a urine and blood test at least once a year. If you've already been diagnosed with CKD, your health care provider may do more frequent urine and blood tests to track any changes in kidney function and adjust your treatment plan. Talk to your healthcare provider about developing a testing schedule that's right for you.

How do I understand my results?

Your healthcare provider will evaluate your uACR results with other tests and your overall health. If your levels are elevated, further testing or treatment may be recommended to manage and protect your kidney function.

Normal uACR

A uACR below 30 mg/g is generally considered normal healthy kidney function. It means the test found no albumin (protein) in your urine, or an amount that is normal. 

Moderate uACR 

A uACR between 30 and 300 mg/g means the test found some albumin (protein) in your urine. This presence of protein can mean your kidneys have moderate damage and are not working as well as they should. If this level remains high for 3 or more months, it may indicate you have chronic kidney disease. It's often a signal to monitor kidney health more closely, especially if you have risk factors like diabetes or high blood pressure.

High uACR 

A uACR over 300 mg/g indicates a higher level of albumin in the urine, which may be a sign of more significant kidney damage or advanced chronic kidney disease (CKD). If this level remains high for 3 or more months, it may indicate you have chronic kidney disease.

Other tests for kidney health

uACR test results are often evaluated alongside your estimated glomerular filtration rate (eGFR), which is also used to evaluate kidney function and detect early signs of CKD.

Learning about other kidney tests can empower you and your doctor to catch kidney disease early — when you can take steps to slow the damage to your kidneys. With the right tests, your doctor can identify the cause of kidney disease, develop a personalized treatment plan tailored to your needs, and help improve your quality of life. Doctors may sometimes rely on eGFR alone without doing a uACR test, but both tests are important to get a full picture of your kidney health. If you haven't had a urine test, ask your doctor to include one.

Your doctor may recommend additional tests to detect kidney disease early, when treatment is most effective. These tests can also help find the cause of kidney disease, allowing your doctor to create a personalized treatment plan to manage to improve your quality of life.