Albumin Creatinine Ratio (ACR) / Urine For Microalbuminuria Test

Albumin is a normal protein found in the blood. Healthy kidneys act like filters and prevent albumin from passing into the urine. But when there is damage to the kidneys, it causes higher amounts of albumin can leak into the urine. The urine albumin test measures how much albumin is leaking into urine. As urine concentration varies based on hydration, this is usually measured as the albumin creatinine ratio (ACR) for standardisation of results.

The ACR is the amount of albumin present in the urine as compared to creatinine, a normal waste product. It is also called as urine albumin creatinine ratio (UACR), urine albumin, albumin creatinine ratio. The UACR test is generally used by doctors to assess kidney health and kidney disease associated with conditions such as diabetes and hypertension. It is a reliable indicator of chronic kidney disease (CKD) or nephropathies, where it helps in assess the risk of kidney damage before symptoms appear, classifying the stage, and guiding treatment and monitoring.

Albumin creatine ratio test is a tool widely used to screen for kidney disease.

This test may be recommended if the following symptoms are present :

• Foamy/bubbly urine
• Decreased urine output
• Swelling around the feet, legs, ankle or around the eyes
• Nocturia (increased urination at night)
• Haematuria (blood in urine)
• Poor appetite and fatigue
• Unexplained nausea and vomiting
• Unintentional weight loss

Following are the patients in whom ACR test may be advised:

• Patients with chronic kidney disease
• Diabetic patients
• Individuals with high blood pressure
• Heart disease patients
• People with family history of diabetes, blood pressure or kidney disease
• Individuals who smoke or are obese
• Those who are over 50 years of age

How often should an individual take ACR test depends on their health situation, whether they are suffering from diabetes, CKD, hypertension or any other risk factors. The following table shows the recommended frequency for ACR test for different health scenarios.

An albumin creatinine ratio test helps in detecting following conditions:

• Chronic kidney disease: Long-term condition in which kidneys develop damage or do not function normally for more than 3 months.
• Acute kidney disease: A condition in which kidneys do not function normally or develop damage, and this problem lasts for up to three months.
• Glomerulopathy: This is a condition associated with kidney’s filtering units which may become damaged and do not remove waste effectively from the body.
• High risk of hypertension or cardiovascular conditions in chronic kidney disease.
• Diabetic kidney disease in adults and children.

What to Expect Before the ACR Test

Collect first morning urine - overnight urine has the highest bacterial concentration. Do NOT start antibiotics before collecting the sample. Clean the genital area before collection using a sterile wipe or clean water to reduce contamination. If the sample cannot reach the lab within 2 hours, refrigerate it at 2 to 8°C - bacteria multiply rapidly at room temperature and can give a falsely high colony count.

What to Expect During the Sample Collection

Open the sterile container without touching the inside or lid. Clean the genital area with two or three gauze pads saturated with soapy water, using a forward-to-back motion, then rinse with sterile saline and water. Begin urinating into the toilet. After the first few drops, collect the middle stream directly into the container without stopping. This midstream clean-catch technique flushes out urethral bacteria before collection begins. Close and label the container with your name, date, and time. Hand it to the PharmEasy phlebotomist or deliver it to the lab within 2 hours.

What to Expect After the ACR Test

No recovery time is needed - urine collection is completely painless and non-invasive. Continue drinking fluids normally. Do not start antibiotics until your doctor has reviewed the culture and sensitivity report. Results are available within 24 to 72 hours..

Following is the parameter included in the albumin creatinine ratio test:

Albumin-to-creatinine ratio/ ACR/UACR: It compares the amount of albumin to the amount of creatinine in the urine sample.

• Albumin: It is a protein normally present in blood, which should not leak in the urine. If albumin appears in urine, it may suggest kidney damage. Albuminuria means increased albumin in urine.
• Creatinine: It is a waste product produced from the normal breakdown of muscles and from protein digestion. The presence of Creatinine in urine tells about how well the kidney are functioning and removing waste from the body.

The normal range for Serum Albumin test is less than 30 µg/mg of creatinine.

The urine albumin creatinine ratio (UACR) helps assess kidney health by measuring the amount of albumin in urine relative to creatinine. A lower ACR value is generally better, while higher values may indicate kidney damage and require further evaluation.

A result in the moderate range suggests a higher risk of kidney failure or having a cardiovascular event (heart attack or stroke). A result in the high range indicates a significant risk.

Having two ACR results in moderate or high ranges over 6 months means you have kidney disease.

Potential Risks and Complications:

The test is a simple urine test that is performed using a urine sample collected during routine examination. There are no risks, side effects, or complications associated with the test.

Limitations:

Following are the limitations of UACR test:

• Kidney disease is generally confirmed when there are two high UACR results for three months or more. Therefore, decisions are not typically based on a single test result.
• The doctor usually interprets the UACR test along with other test such as estimated glomerular filtration rate (eGFR) test to have a clear picture of kidney health.
• False-positive results may be seen with heavy exercise, menstruation, infections or sudden increase in blood pressure or sugar occur 24 hours before the test.
• Your healthcare provider may advise you to stop certain medicines or supplements before the test as they may impact the test results.

Urine albumin creatinine ratio test alone does not give a complete picture of kidney health; hence, following tests may further be advised:

• Complete kidney function profile (KFT)
• Estimated glomerular filtration rate (eGFR) test: test which shows how well the kidneys are removing waste materials from the body.
• HbA1c or blood glucose monitoring
• Blood pressure measurements
• Serum electrolytes
• Kidney imaging such as ultrasound