Albumin-to-Creatinine Ratio (ACR)
For the early detection of kidney disease
Last updated on: July 7, 2025
ACR Calculator
What is the ACR?
The Urine Albumin-to-Creatinine Ratio (ACR or UACR) is a test that measures the amount of albumin in the urine relative to the amount of creatinine. Since creatinine is excreted at a relatively constant rate, this ratio corrects for variations in urine concentration.
It is the preferred test for detecting elevated protein in the urine (albuminuria), which is an early sign of kidney damage.
Why is ACR a Key Test?
- It is highly sensitive for detecting small amounts of albumin (microalbuminuria) before significant kidney damage occurs.
- Crucial for monitoring kidney health in patients with diabetes and hypertension, the two leading causes of chronic kidney disease (CKD).
- The level of albuminuria, as measured by ACR, helps in staging CKD and predicting the risk of progression.
Interpreting the Result (Albuminuria Categories)
A1: Normal to Mildly Increased (< 30 mg/g):
This is the normal range. No significant albuminuria is detected.
A2: Moderately Increased (30-300 mg/g):
Previously known as microalbuminuria. This indicates early-stage kidney disease.
A3: Severely Increased (> 300 mg/g):
Previously known as macroalbuminuria. This indicates more significant kidney damage.
Managing Albuminuria and Kidney Health
Elevated ACR levels indicate kidney damage. Management focuses on treating the underlying cause and slowing the progression of kidney disease.
This page has been medically reviewed by Dr. Khoulah Attia – PharmD, Immunology Specialist.