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Test Code MG Magnesium

Collection Container

Serum gel

Specimen Required


Other Acceptable Specimen Types

Heparinized plasma

Specimen Volume

1 mL

Minimum Specimen Volume

0.1 mL

Transport Temperature


Specimen Stability

Room temperature: 7 days, Refrigerated: 7 days, Frozen: 1


Spectrophotometric; xylidyl blue

Reference Ranges

13-19 mEq/L
Critical: <0.8 mEq/L or >4.5 mEq/L. If from: Obstetrics OR, Labor
and Delivery, or W1 or2: <0.8 mEq/L or >7.0 mEq/L

Turnaround Time

24 hours for routine, 1 hour for stats

Day(s) and Time(s) Performed

Test performed daily

Additional Information

Hemolysis will yield elevated results In very rare cases,
gammopathy, in particular type IgM (Waldenstrom ’s
macroglobulinemia), may cause unreliable results

CPT Code


Units of Measure


Criticals Results

<0.8 mEq/L or >4.5 mEq/L. If from: Obstetrics OR, Labor & Delivery, or W1 or2: <0.8 meq/l or >7.0 meq/L