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Serum/Plasma Creatinine-to-Blood Urea Nitrogen Ratio Confirmation Test

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

This test measures the ratio of creatinine (a waste product from muscle metabolism) to blood urea nitrogen (a measure of kidney function) to help assess kidney health.

Quick summary

["This ratio helps doctors evaluate kidney function and identify potential kidney disease early."]

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

Key facts at a glance

LOINC
50410-0
Short code
dRVVT screen to confirm ratio
Synonyms
dRVVT screen to confirm ratio
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
true
Population
adult
Sex
all
Age range
18–65 years
Method
coag
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 Is Done

Your doctor may order this test if they suspect kidney problems, such as chronic kidney disease, or if you have symptoms like fatigue, swelling, or changes in urine output. It can also be used to monitor kidney function in people with diabetes or high blood pressure.

How the Test Works

A small blood sample is taken to measure both creatinine and blood urea nitrogen levels. The ratio of these two substances is then calculated to provide an overall assessment of kidney function.

What to Expect Before the Test

No special preparation is needed for this test. You may have a slight bruise or soreness at the needle insertion site, but it usually goes away quickly.

What the Results Mean

The ratio itself doesn’t have a standard reference range, but it helps compare how well your kidneys are filtering waste products. High ratios may indicate kidney issues, while low ratios could suggest dehydration or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test is particularly useful for detecting early kidney dysfunction because it provides a snapshot of how efficiently your kidneys are processing waste products. It can help rule out kidney disease or guide treatment decisions, especially in patients with chronic conditions like diabetes or hypertension.

Short name

Creatinine-to-BUN Ratio Confirmation

Frequently asked questions

How long does it take to get the results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing time. Your doctor will contact you with the findings once they are ready.
Can I eat or drink before this test?
You can eat and drink normally before this test, as no special diet or fasting is required.
Is there any risk or discomfort associated with this test?
The most common discomfort is a minor bruise or slight pain at the needle site, which usually resolves quickly. Rarely, there may be a small risk of infection or excessive bleeding, but these are minor risks.
  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