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BCH Order Code MGR Magnesium, RBC

Additional Codes

Quest test code = 623

Performing Laboratory

Quest Diagnostics - Nichols Institute

27027 Tourney Road

Valencia, CA  91355-5386


Specimen Requirements

  1. Patient should refrain from taking vitamins, or mineral herbal supplements for at least one week before sample collection
  2. Preferred Specimen(s) - 0.5 mL packed cells collected in an EDTA (lavender-top or dark blue-top) tube
  3. Minimum Volume - 0.2 mL RBCs - 0.5 mL whole blood
  4. Alternative Specimen(s) - 1 mL whole blood collected in: EDTA (lavender-top) tube or EDTA (royal/dark blue-top) tube
  5. Collection Instructions - Centrifuge to separate plasma from RBCs and discard plasma.  Transfer RBCs to a plastic screw cap vial.  Do not centrifuge whole blood.  Send specimen refrigerated.


Specimen Transport Temperature



Inductively Coupled Plasma/Mass Spectrometry (ICP/MS)

Reference Values

4.0 - 6.4 mg/dL

Day(s) Test Set Up

Tuesday through Saturday

Test Classification and CPT Coding

CPT = 83735

LOINC Code Information