Fetal Renal Pelvis Diameter Measurement (Ultrasound)
This test measures the size of your baby’s renal pelvis (the area around the kidneys) using ultrasound. It helps assess kidney development and detect potential issues.
["Helps monitor kidney growth and identify possible developmental concerns during pregnancy."]
Key facts at a glance
- LOINC
- 11808-3
- Short code
- Fet Renal pelvis-L Diam US.meas
- Synonyms
- Fet 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
What This Test Measures
The renal pelvis is an important part of the fetal urinary system. This measurement helps evaluate whether the kidneys are developing normally and if fluid is flowing correctly through the urinary tract. Abnormal findings may signal conditions like hydronephrosis (swelling due to blocked urine flow).
When This Test Is Done
This test is typically performed during prenatal ultrasounds, often between 18 and 22 weeks of pregnancy, but may be repeated at other times if needed. It’s part of routine fetal anatomy screening.
How the Test Works
A trained technician uses high-frequency sound waves (ultrasound) to create images of your baby’s kidneys. The technician measures the diameter of the renal pelvis in millimeters, comparing it to expected fetal size ranges.
What the Results Mean
Results are interpreted in relation to your baby’s gestational age. A measurement outside typical ranges may prompt further evaluation, such as additional ultrasounds or genetic counseling, depending on the cause.
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: This measurement is critical for identifying potential urinary tract obstructions or kidney abnormalities early in pregnancy. Early detection allows for timely medical intervention if needed, improving both maternal and fetal outcomes.
Short name
Fetal Pelvis Diameter
Frequently asked questions
Why might I need this test?
What does an abnormal result mean?
How often will I need 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