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Order Code MG Magnesium, Plasma or Serum

Specimen Requirements

Collection Container/Tube:

Preferred: Green-top (lithium heparin) gel tube.

Acceptable: Plain, red-top tube or a serum gel tube

Specimen Volume: 2 mL

Pediatric (minimum) volume: 0.5 mL in a green top (lithium heparin) MICROTAINER gel tube

Specimen Minimum Volume

0.5 mL

Performing Laboratory

Ridgeview Medical Center Laboratory

Two Twelve Medical Center Laboratory

Sibley Medical Center

Day(s) Test Set Up

Monday through Sunday


Bichromatic endpoint

Specimen Transport Temperature


Specimen Type Temperature Time
Serum/plasma Ambient 7 days
  Refrigerated (preferred) 7 days
  Frozen 12 months


Test Classification and CPT Coding


Useful For

Quanitative determination of magnesium

Reference Values

1.8-2.4 mg/dL

Critical values (automatic call-back):

Low:  <1.0 mg/dL

High:  >5.0 mg/dL