A urine ACR test, or Albumin-to-Creatinine Ratio, is a simple test to assess kidney health. It measures substances in your urine to show how well your kidneys are functioning. It helps identify potential kidney issues early, often before symptoms appear. Early detection allows for timely management, which can help preserve kidney function.
Understanding the ACR Test
The ACR test measures two substances: albumin and creatinine. Albumin is a protein naturally found in your blood. Healthy kidneys keep this protein in the bloodstream, allowing little to pass into urine.
Creatinine is a waste product from muscle tissue breakdown and protein digestion. Kidneys filter creatinine from blood, and it is present in urine. The ACR test calculates the ratio of albumin to creatinine, which helps account for variations in urine concentration, offering a more reliable assessment of kidney function than measuring albumin alone. This test screens for and monitors kidney damage, especially in individuals with risk factors like diabetes or high blood pressure.
How the Test is Collected
Collecting a urine sample for an ACR test is a straightforward process. A single-spot urine sample is collected, often a first-morning sample, but it can be done at any time. You receive a specimen cup and cleansing wipes for a “clean catch” method, which prevents contamination.
This method involves washing hands, cleaning the genital area, and collecting a midstream urine sample. Urinate a small amount into the toilet first, then stop, position the cup, and collect the sample. After filling the cup to the instructed level, finish urinating in the toilet, cap the container, and return it to the healthcare provider or lab.
What Your ACR Results Mean
ACR results are reported in milligrams per gram (mg/g) and reflect the ratio of albumin to creatinine. A normal ACR result is less than 30 mg/g, indicating kidneys are functioning as expected with minimal albumin leakage.
ACR levels between 30 and 299 mg/g indicate microalbuminuria, suggesting early kidney damage. Levels at or above 300 mg/g signify macroalbuminuria, pointing to more significant kidney damage and a higher risk of kidney failure. Consistently higher numbers suggest more albumin in urine and progressive kidney damage. Repeat testing over several months is recommended to confirm elevated results and differentiate between temporary fluctuations and persistent kidney issues.
Next Steps After Abnormal Results
An abnormal ACR result, especially if consistently elevated, suggests kidneys may not be filtering waste effectively. Common underlying causes for elevated ACR include uncontrolled diabetes, high blood pressure, and other kidney diseases like glomerulonephritis or autoimmune conditions. Temporary factors such as fever, intense exercise, or urinary tract infections can also cause a transient increase in albumin levels.
If your ACR test shows abnormal levels, your healthcare provider will recommend follow-up tests to confirm findings and investigate the cause. These may include additional ACR tests, an estimated glomerular filtration rate (eGFR) blood test to assess kidney function, or imaging tests like an ultrasound. Managing underlying conditions through lifestyle modifications, such as diet and exercise, and medication adjustments can help reduce albumin levels and slow kidney damage progression. Consulting with a healthcare provider for personalized advice and a comprehensive management plan is an important step.