Sign in →

Test Code 0204 Magnesium, Urine, Random

Performing Laboratory

Barnes-Jewish Hospital Laboratory


Colorimetric (Xylidyl Blue)

Literature Reference:

Package insert: Magnesium MG2 reagent. Roche Corporation, 03/2015.

Specimen Requirements

Specimen Type: Urine, random
Container/Tube: Urine Complete Cup Kit
Specimen Volume: 10 mL

Collection Instructions: No additive.
Additional Information: See Urine Collection in Special Instructions for additional information.

Day(s) Test Set Up

Monday through Sunday
Turnaround Time:
STAT: 1 hour after receipt in laboratory
Routine: 2 to 4 hours after receipt in laboratory

Reference Values

No established reference intervals

Literature Reference:

Tietz, Burtis CA, Ashwood ER, Bruns DE eds: Textbook of Clinical Chemistry and Molecular Diagnostics 5th ed: Chapter 52, p. 1733, Elsevier, St. Louis, MO 2012. 

Test Classification and CPT Coding


Additional Information

For BJH Laboratory Use Only

Analyte Stability:

See Analyte Stability Chart in Special Instructions.

Specimen must be kept refrigerated before delivery to limit bacterial growth.

Laboratory Processing Instructions:

Test performed in BJH Core lab. Mix urine well. Using 13x100 test tubes, prepare a 7-mL save-tube and refrigerate. The urine specimen must have a pH between 2.0 and 4.5. If the pH is not within these limits, the pH must be adjusted with 6N HCl. Carefully add 6N HCl to the entire collection in 1 drop increments.  After pH adjustment, the specimen should then be mixed well again. Heat for 10 minutes at 56° C. Deliver to the automated line for centrifugation and delivery to Cobas 8000 for analysis. Completed specimen is stored refrigerated for 5 days. 

Specimen Transport Temperature


LOINC Code Information

Name LOINC Code
Magnesium in urine 19124-7