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Urinary Albumin-to-Creatinine Ratio (UACR) or Albumin-to-Creatinine Ratio (ACR)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of albumin (a protein) in your urine compared to creatinine (a waste product from muscles), helping assess kidney function and early kidney damage.

Quick summary

["A UACR/ACR helps detect kidney problems early, often before symptoms appear."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
98631-5
Short code
SNAP area AUC L ulnar n
Synonyms
SNAP area AUC L ulnar n
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nerve-conduction
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

Why This Test Matters

Your kidneys normally filter waste and extra fluid from your blood. Albumin is a protein that should stay in your bloodstream, but if small amounts leak into urine, it can signal kidney strain. Creatinine is a stable waste product that helps balance this comparison, ensuring the test reflects true kidney health.

How It Works

A small urine sample is collected, typically over a 24-hour period or a single random sample. The lab measures albumin and creatinine levels and calculates their ratio. This ratio helps identify if albumin is leaking into urine at a rate that might indicate kidney issues.

When It’s Ordered

Doctors may order this test if you have risk factors for kidney disease (e.g., diabetes, high blood pressure, family history), symptoms like swelling, frequent urination, or fatigue, or if you’re being monitored for chronic conditions.

What to Expect

You’ll likely collect urine in a container for a set time (e.g., 24 hours) or provide a single random sample. No special preparation is needed, but drink plenty of water to ensure a good urine sample. Results are usually ready within a few days.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A UACR/ACR above a certain threshold (varies by lab) often signals **microalbuminuria**, a key early sign of kidney damage, especially in people with diabetes or high blood pressure. Higher ratios may indicate worsening kidney function over time, guiding treatment decisions like blood pressure control or diabetes management.

Short name

UACR/ACR

Frequently asked questions

How often should I get this test?
Your doctor will determine how often based on your health status. For example, people with diabetes may get it checked yearly, while others with kidney risk factors might need it more frequently.
What do my results mean?
Results are usually reported as a ratio (e.g., mg/mg or mg/g). A normal result is typically below a specific threshold, but your doctor will interpret it in the context of your overall health. Ask your doctor to explain what your ratio means for you.
Can I change my diet before this test?
No special diet is needed, but avoid very high-protein or very low-protein foods for 24 hours before a 24-hour urine collection, as this could affect results. Drink water as usual to help your kidneys produce enough urine.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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