What does ACR stand for in a kidney-related context?

• A. Albumin-Creatinine Ratio
• B. Arterial Creatinine Ratio
• C. Albumin-to-Creatinine Ratio
• D. Antigen-Creatinine Ratio

Answer: (C)

ACR stands for Albumin-to-Creatinine Ratio. This test measures how much albumin is being lost in the urine, but it accounts for how concentrated the urine is by normalizing to creatinine in the same sample. That normalization makes the result more reliable than a simple urine albumin level, since urine concentration can vary widely. Clinically, ACR is used to screen for kidney damage and to monitor conditions like diabetes and hypertension; results are given in mg of albumin per g of creatinine (mg/g). Normal values are typically under about 30 mg/g, with higher values indicating increasing albuminuria.

Arterial Creatinine Ratio isn’t used for assessing urinary albumin loss, and Antigen-Creatinine Ratio isn’t a relevant measure in this context. Albumin-Creatinine Ratio is essentially the same idea, but the standard terminology in guidelines is Albumin-to-Creatinine Ratio.