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Test Code LAB103 Magnesium

Department

CHEMISTRY

Primary Collection Container

Green PST (Lithium Heparin)

Alternate Collection Container

Green Microtainer PST

Transport

Plasma refrigerated

Preferred Transport Temperature

Refrigerated

Processing

Centrifuge and refrigerate.

Separate from cells within 2 hours.

Stability

Refrigerated: 48 hours

Minimum Testing Volume

0.1 mL

Reference Range

1.8 – 2.4 mg/dL

Methodology

The magnesium method is a modification of the methylthymol blue (MTB) complexometric procedure described by Connerty, Lau, and Briggs. MTB forms a blue complex with magnesium. Calcium interference is minimized by forming a complex between calcium and Ba-EGTA (chelating agent). The amount of MG-MTB complex formed is proportional to the magnesium concentration and is measured using a bichromatic (600 and 510 nm) endpoint technique. Siemens Dimension Vista and ExL.

Performed

Sunday – Saturday

Reported

As completed

CPT Codes

83735

Unacceptable Conditions

Hemolysis.