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Test ID MGS Magnesium, Serum

Useful For

Monitoring preeclampsia patients being treated with magnesium sulfate, although in most cases monitoring clinical signs (respiratory rate and deep tendon reflexes) is adequate and blood magnesium levels are not required

Method Name

Colorimetric Assay

Reporting Name

Magnesium, S

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Collection Instructions:

1. See Trace Metals Analysis Specimen Collection and Transport for complete instructions.

2. Serum gel tubes should be centrifuged within 2 hours of collection.

3. Red-top tubes should be centrifuged and aliquoted within 2 hours of collection.

Additional Information: If other metal tests are also desired when drawing for a serum magnesium level; the specimen must be drawn in a plain, royal blue-top Vacutainer plastic trace element blood collection tube.

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  365 days

Reference Values

0-2 years: 1.6-2.7 mg/dL

3-5 years: 1.6-2.6 mg/dL

6-8 years: 1.6-2.5 mg/dL

9-11 years: 1.6-2.4 mg/dL

12-17 years: 1.6-2.3 mg/dL

>17 years: 1.7-2.3 mg/dL

Day(s) Performed

Monday through Sunday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
MGS Magnesium, S 19123-9


Result ID Test Result Name Result LOINC Value
MGS Magnesium, S 19123-9

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

Report Available

Same day/1 to 2 days

NY State Approved