Sign in →

Test Code 1522 Magnesium, Plasma

Performing Laboratory

Barnes-Jewish Hospital Laboratory


Colorimetric (Xylidyl Blue)

Literature References:

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

Specimen Requirements

Specimen Type: Plasma
Container/Tube: Mint-green top (lithium heparin)
Specimen Volume: Full tube


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

1.4-2.5 mg/dL
Critical result (automatic call-back):
Non-labor and delivery patients: ≤0.4 mg/dL or ≥4.8 mg/dL
Labor and delivery patients: ≤0.4 mg/dL or ≥7.3 mg/dL

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
Alternate Tube:

1 dark green-top (lithium heparin) tube
1 red-top tube
Analyte Stability:

See Analyte Stability Chart in Special Instructions.

Laboratory Processing Instructions:
Test performed in BJH Core Lab.  Processed by automated line for delivery to the Cobas 8000. Test performed in North Campus Laboratory. Centrifuge upon receipt and deliver to the Modular. Completed specimens are stored refrigerated for 5 days. 

Specimen Transport Temperature


Special Instructions

LOINC Code Information

Name LOINC Code
Magnesium 19123-9