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HelpTest Code NITU Nitrogen, Total, 24 Hour, Urine
Reporting Name
Nitrogen, Total, UUseful For
Assessing nutritional status (protein malnutrition)
Assessment of protein nutrition and nitrogen balance in hospitalized patients
Evaluating protein catabolism
Determining nitrogen balance, when used in conjunction with 24-hour fecal nitrogen measurement
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineNecessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 10 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. No preservative. Refrigerated is the preferred preservation method.
Specimen Stability Information: Frozen 3 years
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections
Specimen Minimum Volume
2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 7 days | |
| Ambient | 7 days | ||
| Frozen | |||
Special Instructions
Reference Values
<16 years: Not established
≥16 years: 4-20 g/24 hours
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84999
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| NITU | Nitrogen, Total, U | 2660-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 17418 | Nitrogen, Total, U | 2660-9 |
| DUR8 | Collection Duration | 13362-9 |
| TOTV | Specimen Volume | 28009-9 |
Interpretation
Urinary nitrogen excretion levels within the normal range are indicative of adequate nutrition.
Slightly abnormal excretion rates may be a result of moderate stress or complications, such as infection or trauma.
Significantly abnormal excretion rates may be associated with severe stress due to multiple traumas, head injury, sepsis, or extensive burns. The goal with therapy for a depleted person is a positive nitrogen balance of 4 to 6 g nitrogen/24 hours.
Clinical Reference
1. Morse MH, Haub MD, Evans WJ, Campbell WW. Protein requirement of elderly women: nitrogen balance responses to three levels of protein intake. J Gerontol A Biol Sci Med Sci. 2001;56(11):M724-730
2. Phinney SD: The assessment of protein nutrition in the hospitalized patient. Clin Lab Med. 1981;1:767-774
3. Konstantinides FN, Kostantinides NN, Li JC, Myaya ME, Cerra FB. Urinary urea nitrogen: too insensitive for calculating nitrogen balance studies in surgical clinical nutrition. J Parenter Enteral Nutr. 1991;15(2):189-193
4. Borowitz D, Konstan MW, O'Rourke A, Cohen M, Hendeles L, Murray FT. Coefficients of fat and nitrogen absorption in healthy subjects and individuals with cystic fibrosis. J Pediatr Pharmacol Ther. 2007;12(1):47-52. doi:10.5863/1551-6776-12.1.47
5. Dickerson RN: Nitrogen balance and protein requirements for critically ill older patients. Nutrients. 2016;8(4):226. doi:10.3390/nu8040226
Method Name
Dumas Combustion
Day(s) Performed
Friday