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Test Code MG Magnesium Serum

Clinical System Name

Magnesium Serum


Magnesium deficiency may cause weakness, tremors, tetany, and convulsions.  Hypomagnesemia is associated with hypocalcemia, alcoholism, some types of malnutrition, malabsorption, chronic hemodialysis, and pregnancy.  Increased serum magnesium concentrations occur in patients with renal failure, dehydration, and Addison’s disease.  

Sample Requirements

Specimen: Whole Blood

Container(s):  Gold SST, Dark Green/Sodium Heparin, Red, Gold Microtainer, Lt. Green/Li Heparin Microtainer, or Heparinized Syringe

Preferred Vol:  1.0 mL

Minimum Vol:  0.5 mL


Notes: Method is affected by hemolysis, EDTA, Na F-oxalate. Not affected by lipemia.


Processing Instructions

Reject due to:  Insufficient quantity, incorrect specimen container, hemolysis

Spin: Y

Aliquot: Y

Temp:  2-8oC

Storage location:  Core Chemistry Refrigerator


Off-site collection: Avoid hemolysis. Spin blood, separate serum/plasma from cells.



Specimen Type Temperature Time
Serum or Plasma RT

7 D

Serum or Plasma 2-8oC

  7 D

Serum or Plasma -20oC or -70oC

30 D



STAT Performed TAT
Y 24/7 1 H


Performing Laboratory

Seattle Children's Laboratory    


Department:  Core Chemistry

Phone Number: 206-987-2617



Reference Range


1.8 - 2.4 mg/dL


Method:  Colorimetric method by Vitros 4600

Analytical Volume:  0.02 mL + 0.03 mL dead space

CPT Codes


Critical Values

≤ 1.0 mg/dL

≥ 5.0 mg/dL