Click here for more information about laboratory operations and procedures
If you have additional questions regarding this test, please call: 415-353-1667
Magnesium, 24 hour urine
|Approval req'd?||Yes, if testing is requested between midnight and 8:00 AM.|
|Performed by||Parnassus Chemistry|
|In House Availability||Test available 7 days per week from 8:00 AM to midnight only.|
|Method||Spectrophotometric (calmagite dye)|
|Collection Instructions||Keep container refrigerated during collection. Indicate hours of collection on requisition.|
|Container type||24 hour urine collection container
Click here for Urine Preservative Requirements
|Amount to Collect||Entire 24 hour urine output.|
|Sample type||24 hour urine collection|
|Preferred volume||2 mL urine|
|Min. Volume||1 mL urine|
|UCSF Rejection Criteria||Container not refrigerated during collection.|
|Processing notes||Aliquot 2 mL and add 1 drop of 6N HCl to acidify.|
|Normal range||73-122 mg/D
See Additional information.
|Stability||Refrigerated 2 days|
|Turn around times||Test run 2x daily. Results available at 1400 & 2000|
|Additional information||Output varies with the diet.
To convert mg/d to mmol/d (SI units) multiply by x 0.411.
Gadolinium MR contrast agents including Gadodiamide (Omniscan), Gadoversetamide (Optimark), Gadopentetate Dimeglumine (Magnevist), and Gadoterdiol (Prohance), have been shown to interfere with certain colorimetric assays used in the measurement of various serum cations including iron, magnesium, and calcium. The UCSF clinical labs utilize a colorimetric assay for the measurement of both serum iron and serum magnesium that are subject to this interference. For serum magnesium, some gadolinium containing agents (Gadodiamide and Gadoversetamide) may produce a falsely elevated result (on average 117 and 124% respectively, of the true serum magnesium concentration). See "Calcium" and "Iron" entries for respective interferences.
Reference:Proctor et al. Gadolinium Magnetic Resonance contrast Agents produce Analytic Interference in Multiple Serum Assays. Am J Clin Pathol. 2004;121:282-292.
|Last Updated||3/24/2013 7:46:08 PM|
|Lab Procedure Link||Click here for Procedure|