Laboratory Test Information Guide

Details for Magnesium,Plasma

Test Name: Magnesium,Plasma
Alternate Name(s):  
Laboratory: Core
Specimen Type: 4.5 mL Green (Lithium Heparin) top Vacutainer tube

0-2 years: 0.5 mL Green top Microtainer
2-10 years: 2 mL Green top Vacutainer tube
Collection Information: Collect blood aseptically in a Vacutainer tube.

Minimum volume required for a pediatric sample is 0.2 mL

Test Schedule: As required.
Turnaround time from when specimen
is received in testing laboratory:
4 hours
1 hour
Reference Range: 0.65-1.05 mmol/L
Effective Date: 2008-11-15
Revised Date: 2012-11-20
Critical Value: Low: <0.5 mmol/L; High: >2.00 mmol/L to be phoned to Nurse or Physician immediately
Interpretive Comments: Useful in the diagnosis of hypomagnesaemia as the cause of unexplained cardiac arrhythmias, tetany, neuromuscular disorders, and refractory hypocalcaemia/hypokalaemia.

Useful to monitoring magnesium sulphate during anticonvulsant therapy (especially in pre-eclampsia) or therapy causing renal magnesium loss (e.g. cisplatinum).

Plasma/serum magnesium levels do not correlate well with intracellular levels, thus this test is not sensitive for detecting chronic deficiency because of compensatory contributions from bone.

Levels fall rapidly in response to reduced intake and may not reflect tissue levels.
Special Processing:  
Comments: Reference Ranges are based on Non-Occupationally exposed population.
Method of Analysis: Colorimetric endpoint
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Referred To:  

Questions? Comments? Contact Laura Gopaul