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Red Blood Cell Urine Protein-to-Creatinine Ratio (UPCR)

Published: August 9, 2026Updated: August 17, 2026

This test measures the ratio of protein in your urine to a small protein called creatinine, which comes from muscle breakdown. It helps assess how much protein is being lost in your urine over time.

Quick summary

["A useful tool for detecting and monitoring kidney-related protein loss."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
105090-5
Short code
RBC UrnS Ql
Synonyms
RBC UrnS Ql
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85041
SNOMED
900000000000003001
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test to check for conditions like kidney disease, where the kidneys might not filter proteins properly. It’s often used alongside blood tests to monitor kidney function or diagnose issues like nephrotic syndrome or diabetic kidney disease.

What to Expect Before the Test

You’ll likely provide a urine sample in the morning after fasting (no food or drink except water) for about 2–3 hours. Follow your doctor’s instructions carefully to ensure accurate results.

How the Test Works

The urine sample is tested to measure protein levels and creatinine. The ratio helps standardize results by accounting for urine concentration, so even small volumes can be compared fairly.

Possible Results and Next Steps

If your ratio is higher than expected, it may indicate kidney problems or other conditions affecting protein loss. Your doctor will discuss findings with you and may recommend further testing or adjustments to your treatment plan.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: urine

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Detecting and Managing Kidney-Related Protein Loss

Short name

Urine Protein-to-Creatinine Ratio

Frequently asked questions

What does a high or low urine protein-to-creatinine ratio mean?
A high ratio often signals kidney damage or disease, such as glomerulonephritis or diabetic nephropathy, where proteins escape into urine. A low ratio may suggest normal kidney function or conditions like dehydration, but further evaluation is needed to rule out other causes.
Can diet affect this test?
Yes, high-protein diets or certain medications (like NSAIDs) may temporarily alter protein levels in urine. Avoiding these factors for 24–48 hours before testing can improve accuracy.
Is this test painful or uncomfortable?
No, this is a simple urine sample test—just collect a midstream urine sample in a clean container. No needles or discomfort are involved.
  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 17, 2026. · Read our editorial policy