ACR

In screening guidelines, ACR usually means the American College of Radiology, which publishes recommendations such as those for breast cancer screening, or the American College of Rheumatology, which publishes criteria for diagnosing diseases such as lupus. On a urine lab report, ACR is the albumin-to-creatinine ratio, a test for early kidney damage, especially in diabetes and high blood pressure. The setting tells you which is meant.