This page explains a medical test in patient-friendly terms, covering what it checks, why your healthcare provider may order it, and how it fits into your diagnosis, treatment, or preventive care.
This test measures the urea nitrogen level in peritoneal dialysis fluid to evaluate how effectively dialysis is removing waste products from your body.
{"Measures urea nitrogen concentration in peritoneal dialysis fluid","Helps assess if dialysis is adequately removing waste from your blood","Results guide adjustments to your dialysis treatment plan","Typically collected during a routine dialysis exchange","Results are interpreted together with other kidney function tests"}
Key facts at a glance
- LOINC
- 14936-9
- Short code
- Urea nitrogen PD fluid
- Synonyms
- Urea nit DiafP-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Clean sterile container for dialysis effluent collection
- Units
- not specified
- Ref low
- 7
- Ref high
- 20
- Critical range
- — – 100 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Enzymatic ultraviolet assay or colorimetric assay
- CPT
- 90935 or 90945 (Peritoneal dialysis evaluation)
- SNOMED
- 236435004
- Specimen volume
- Complete collection of dialysis effluent, typically 24-hour volume
- Stability
- Refrigerate if analysis delayed beyond 24 hours; stable at 2-8°C for up to 72 hours
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What does this medical test measure, and why might my healthcare provider recommend it as part of my evaluation?
The peritoneal dialysis fluid urea nitrogen test measures the amount of urea nitrogen in the dialysis solution that has been in your abdomen for a period of time. Urea nitrogen is a waste product that comes from the breakdown of protein in your body. Healthy kidneys filter this waste out of your blood, but when kidneys fail, dialysis helps remove it instead.
How is the test performed, what should I expect during the visit, and how can I prepare to make it safer and more accurate?
During a regular peritoneal dialysis exchange, a sample of the used dialysis fluid is collected before draining it from your abdomen. The sample is sent to a laboratory where the urea nitrogen concentration is measured. This is usually done as part of your routine dialysis care appointments.
Why is this test important, how do the results affect my diagnosis or care plan, and what follow-up questions should I ask my care team?
This test helps your healthcare team understand how well your peritoneal dialysis is working. By measuring how much urea nitrogen has moved from your blood into the dialysis fluid, doctors can determine if your dialysis treatment is effectively cleaning your blood. If the results show inadequate waste removal, your dialysis prescription may need to be adjusted.
Reference range
Adult: 7-20 mg/dLnot specified
No special preparation or fasting required; collect peritoneal dialysis effluent per protocol
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The peritoneal dialysis fluid urea nitrogen test is a key indicator of dialysis adequacy. A higher urea nitrogen level in the dialysis fluid generally indicates better waste removal. This test is part of a comprehensive assessment that typically includes other measurements like creatinine clearance and total kidney function evaluation. Regular monitoring helps prevent complications from inadequate dialysis, such as fluid overload, electrolyte imbalances, and uremic toxin accumulation. Your healthcare provider will interpret these results in the context of your overall health, other lab values, and clinical symptoms to determine if your current dialysis regimen is optimal.
Frequently asked questions
Do I need to fast before this test?
How often should this test be done?
What do abnormal results mean?
Is this test painful?
Can I do this test at home?
Sources
- 1
- 2
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