Magnesium, 24 Hour, Urine
Use
This test is useful for assessing the cause of abnormal serum magnesium concentrations using a 24-hour urine collection. It helps determine whether nutritional magnesium loads are adequate and is involved in calculating urinary calcium oxalate and calcium phosphate supersaturation to assess kidney stone risk.
Special Instructions
For electronic ordering, complete necessary forms and submit specimen. If not ordering electronically, complete and send a Renal Diagnostics Test Request form with the specimen. Ensure urine is collected over 24 hours, refrigerated within 4 hours of collection completion, and submitted in appropriate containers.
Limitations
Urinary magnesium excretion should be interpreted in conjunction with serum concentrations. In patients with IV magnesium infusion, interpret results with caution as this can affect urinary magnesium levels.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 24447-5
- 24447-5
- 13362-9
- 3167-4
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL
Container
Plastic, 5 mL tube or a clean, plastic urine container with no metal cap or glued insert
Collection Instructions
Collect urine for 24 hours. Refrigerate specimen within 4 hours of completion of 24-hour collection.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 14 days |
| Frozen | 30 days |