Measurement of Diameter of the Renal Pelvis
This test measures the size of your renal pelvis—a funnel-shaped structure in your kidneys that collects urine before it moves to the bladder. It helps assess kidney function and detect potential blockages or structural issues.
["A larger-than-normal renal pelvis may signal kidney problems that need further evaluation."]
Key facts at a glance
- LOINC
- 11809-1
- Short code
- Renal pelvis-L Diam US.meas
- Synonyms
- Renal pelvis-L Diam US.meas
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 44
- Ref high
- 147
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-measured
- CPT
- 84075
- SNOMED
- 27550007
- 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 Is This Test Done?
Your healthcare provider may order this test if you have symptoms like persistent pain in your back or side, frequent urinary tract infections, or signs of kidney stones. It can also be part of a broader evaluation for conditions like hydronephrosis (swelling in the kidney due to urine buildup).
What to Expect During the Test
This is typically a non-invasive procedure. You may undergo imaging like an ultrasound, CT scan, or MRI to visualize the renal pelvis. No special preparation is usually needed, but follow any instructions your provider gives for fasting or avoiding certain foods/drinks.
How the Results Are Interpreted
Results are compared to your size and health. A normal pelvis diameter varies by individual, but abnormal measurements may indicate fluid buildup, structural abnormalities, or other kidney-related concerns that require further testing or treatment.
What Could Abnormal Results Mean?
Larger-than-expected diameters might suggest hydronephrosis, kidney stones, or blockages from tumors or strictures. Smaller diameters could be normal or related to congenital kidney issues. Your provider will discuss findings with you and recommend next steps.
Reference range
Adult: 44-147 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Renal Pelvis Diameter
Frequently asked questions
What are the normal reference ranges for this test?
How often should I get this test?
Can I eat or drink before this test?
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