Serum Creatinine to Albumin Ratio (C/A Ratio) or Albumin-Creatinine Ratio (ACR)
This test measures the ratio of albumin (a protein) to creatinine (a waste product) in your serum. It helps assess kidney function and detect early signs of kidney damage or protein loss in urine.
["A simple blood test to check kidney health and protein loss over time."]
Key facts at a glance
- LOINC
- 109165-1
- Short code
- C trach I Ab Msmt Ser
- Synonyms
- C trach I Ab Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is the Albumin-Creatinine Ratio (ACR) Test Used For?
The ACR test is often used in combination with a urine albumin test to evaluate kidney function, especially in people with diabetes, hypertension, or a family history of kidney disease. It can help detect kidney damage before symptoms appear and monitor progression of kidney disease over time.
How Is the Albumin-Creatinine Ratio Test Performed?
A small blood sample is drawn from your arm. The serum portion is then analyzed to measure both albumin and creatinine levels. The results are expressed as a ratio to compare protein loss relative to kidney function.
Why Might Your Doctor Order This Test?
Your doctor may recommend this test if you have symptoms like swelling, frequent urination, or fatigue, or if you have conditions like diabetes or high blood pressure that increase kidney risk. It’s also used during pregnancy to monitor kidney health.
What Do the Results Mean?
Results are not provided with specific ranges here, as they depend on clinical context. Your doctor will interpret the ratio in relation to your overall health and symptoms to determine if kidney issues are present or worsening.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The ACR test is clinically significant because it provides a quick, non-invasive way to assess kidney function and protein loss. High ratios may indicate kidney disease, while low ratios suggest normal kidney function. It’s particularly useful for monitoring chronic kidney disease (CKD) and guiding treatment plans.
Short name
Albumin-Creatinine Ratio (ACR) Serum
Frequently asked questions
What does a high or low albumin-creatinine ratio mean?
How often should I get this test?
Can lifestyle changes affect my ACR test results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy