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Lab Manual for Moffitt-Long and Mount Zion

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Magnesium, random urine

Item Value
Approval req'd? No
Available Stat? No
Test code MGUR
Test group Magnesium
Performed by Parnassus Chemistry
In House Availability Test available 24 hours per day 7 days per week
Method Spectrophotometric (calmagite dye)
Collection Instructions Refrigerate sample after collection if transport to laboratory is delayed
Container type Urine cup
Amount to Collect 10 mL urine
Sample type Random urine
Preferred volume 2 mL urine
Min. Volume 1 mL urine
Processing notes Aliquot 2 mL urine and add 1 drop of 6N HCl to acidify.
Units mg/dL
Normal range See additional information
Synonyms Mg
Stability Refrigerated 2 days
Turn around times Routine 4 hours
Additional information Output varies with the diet.

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.
CPT coding 82570-90, 83735-90
LOINC code 19124-7
Last Updated 3/24/2013 8:03:15 PM
Entry Number 1171
Lab Procedure Link Click here for Procedure
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