BUN/Creatinine Ratio Test
This test compares blood urea nitrogen (BUN) and creatinine levels in a blood sample to calculate their ratio, a measurement used in the differential diagnosis of acute or chronic kidney disease.
About this test
Blood urea nitrogen (BUN) and creatinine are both markers related to kidney function, and the ratio between them can shift with changes in kidney blood flow, urea production, or liver function. An increased ratio is associated with reduced kidney blood flow, urinary tract obstruction, or increased urea formation such as from gastrointestinal bleeding or trauma, while liver disease is associated with a decreased ratio.
The test uses a 2 mL serum sample to determine BUN and creatinine levels and calculate the ratio between them, along with an estimated glomerular filtration rate (eGFR).
Test details
| Quest code | 296 |
|---|---|
| Methodology | See individual tests |
| Sample type | 2 mL serum |
| Collection | Quest patient service center |
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Quest resources
Additional details
What this test looks at
The test reports BUN, creatinine, eGFR, and the calculated BUN/creatinine ratio. Quest also lists it under the aliases Blood Urea Nitrogen and BUN.
How it's often used alongside other tests
Because the ratio is used in the differential diagnosis of kidney disease, it is typically read together with other kidney-related markers and a person's clinical history, rather than as a single number that identifies a cause on its own.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does this test measure?
It measures blood urea nitrogen (BUN) and creatinine in a serum sample and calculates the ratio between them, along with an estimated glomerular filtration rate (eGFR).
How is the sample collected?
The test uses a 2 mL serum sample collected through a routine blood draw.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Why might this ratio be ordered?
It is used in the differential diagnosis of acute or chronic kidney disease, since changes in the ratio are associated with reduced kidney blood flow, urinary tract obstruction, increased urea formation, or liver disease.
Can I get the BUN/Creatinine Ratio test without a doctor's visit or insurance?
Yes. The $15 cash price includes an independent physician's order, so no referral is needed, and insurance is never involved.