Nitrogen, Total, 24 Hour, Urine

Casandra

Casandra Test Code MC67524Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID NITUCPT Code 84999

Nitrogen, Total, 24 Hour, Urine

Clinical Use

Use

This test is useful for assessing nutritional status (protein malnutrition), assessment of protein nutrition and nitrogen balance in hospitalized patients, evaluating protein catabolism, and determining nitrogen balance when used in conjunction with 24-hour fecal nitrogen measurement. It measures total urinary nitrogen excretion, which is key in evaluating protein catabolism and nutritional status. Urinary nitrogen excretion within normal range indicates adequate nutrition; moderate deviations may reflect stress or trauma; significant deviations may occur in severe stress states such as trauma, sepsis, or burns, with therapeutic goals targeting a positive nitrogen balance of 4 to 6 g nitrogen/24 hours. Citations: Mayo Clinic Labs overview pages ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/607705?utm_source=openai)).

Special Instructions

Uses the Dumas combustion method (unpublished Mayo method). NY State approval for ordering is Yes. Reporting name is "Nitrogen, Total, U"; aliases include "Nitrogen Balance", "Total Urinary Nitrogen", and "TUN". 24-hour urine volume in milliliters is required. Special instructions include referencing the PDF “Urine Preservatives‑Collection and Transportation for 24‑Hour Urine Specimens.” Citations: ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/607705?utm_source=openai)).

Limitations

Urine samples with visible blood may exhibit a positive bias due to nitrogen from hemoglobin, and nitrogen lost from wounds, burns, or sputum must be included in balance studies. Measurement of both urine and fecal nitrogen is necessary for accurate nitrogen balance estimation. Citations: ([mayocliniclabs.com](https://www.mayocliniclabs.com/test-catalog/Overview/607705?utm_source=openai)).

Test Details

New York Approved