Ammonium, 24-Hour Urine
Also known as: AMMO U
Use
The Ammonium, 24-Hour Urine test is used to determine the cause of acidosis and may aid in diagnosing and monitoring kidney stones. It requires a 24-hour urine collection of 300 mL or greater to ensure accurate assessment. Altered levels of ammonium can be indicative of metabolic or kidney disorders, providing insight into the patient's acid-base balance.
Special Instructions
Ensure that the urine sample is refrigerated during the collection period or that it includes 5 mL of diazolidinyl urea (Germall) as a preservative at the start of collection. It is essential to provide the duration of the collection and total urine volume for the test to proceed. If the total volume is less than 300 mL, contact ARUP Client Services for assistance. This test is performed by Mayo Clinic Laboratories, not ARUP.
Limitations
Specimens with a pH greater than 8 may indicate bacterial contamination, leading to test cancellation. Attempts to adjust pH are discouraged as they could adversely affect test results. The test performance characteristics have been determined by Mayo Clinic under CLIA requirements; however, it has not been cleared or approved by the FDA. Reference values are not established for patients under 18 or over 77 years. The presence of sulfasalazine, sulfapyridine, or temozolomide can result in false results.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 25308-8
- 13362-9
- 3167-4
Result Turnaround Time
3-5 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL
Container
ARUP standard transport tube
Collection Instructions
From a well-mixed 24-hour collection, transfer the required volume to a transport tube. Ensure the collection duration and urine volume are provided.
Patient Preparation
Refrigerate during collection or add 5 mL of diazolidinyl urea (Germall) as preservative at the start.
Storage Instructions
Refrigerated storage is preferred; frozen is also acceptable.
Causes for Rejection
Specimens with pH greater than 8 due to bacterial contamination.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 2 weeks |
| Frozen | 2 weeks |