Urine ACR (urine albumin-to-creatinine ratio)
The Urine ACR test measures the ratio of albumin to creatinine in the urine. This test provides insight into the amount of albumin that is excreted into the urine by the kidneys and can help detect early-stage kidney damage.
What is the albumin-to-creatinine ratio (ACR)?
Albumin is a protein that is normally found primarily in the blood. Healthy kidneys retain virtually all of the albumin, so that normally only a small amount ends up in the urine.
When the kidney’s filters become damaged, more albumin may appear in the urine. This can happen even before abnormalities become apparent in, for example, blood creatinine levels or eGFR.
In this test, albumin is compared to the amount of creatinine in the urine. This corrects for the concentration of the urine and provides a more reliable indication of albumin loss.
When might a Urine ACR test be useful?
An ACR test can be used, among other things, to:
to detect early-stage kidney damage;
in cases of diabetes;
in cases of high blood pressure;
in cases of an increased risk of kidney disease;
to monitor existing kidney damage or albuminuria;
As a supplement to kidney function tests, such as blood creatinine and eGFR.
What does an elevated ACR mean?
An elevated ACR indicates that more albumin is being excreted in the urine than usual. This may be consistent with impaired kidney filtration function or kidney damage.
However, an elevated value does not always indicate permanent kidney damage. The ACR may be temporarily elevated, for example, due to intense physical exertion, fever, a urinary tract infection, menstruation, or an acute illness. Therefore, a repeat test may be necessary if the result is abnormal.
Decrease
This test requires a urine sample. The first morning urine is the preferred sample for this test.
Additional Kidney Testing
For a more comprehensive picture of kidney function, the Urine ACR can be combined with blood tests for, for example, creatinine, eGFR, and cystatin C.
