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Test Code BLOD0567 Magnesium, Plasma or Serum

Useful For

  • The evaluation of metabolic disorders and therapy in treatment of pre-eclampsia
  • Monitoring therapy in patients on long-term intravenous infusions


Colorimetric Methylthymol Blue (MTB)/Bichromatic End point

Performing Laboratory

Bozeman Health Laboratory Services

Specimen Requirements

Specimen Type: Plasma or serum
Container/Tube: Light-green top (lithium heparin gel), dark-green top (sodium heparin), red top, or gold top
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL

Collection Instructions: Label specimen as plasma or serum.

Specimen Transport Temperature


Specimen Stability


Specimen Type Temperature Time
Plasma or Serum Ambient 7 days
  Refrigerated 7 days
  Frozen 1 year


Reference Values

1.5-2.1 mg/dL


Critical values (automatic call-back): <1.0 mg/dL or >4.9 mg/dL

Therapeutic range for magnesium sulfate: 4.8-8.4 mg/dL

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding