Laboratory Test Information Guide

Details for Magnesium, 24-Hour Urine

Test Name: Magnesium, 24-Hour Urine
Alternate Name(s):  
Laboratory: Core
Specimen Type: 24 hour urine collected in 24 hour urine container
Collection Information: Collection of 24-Hour Urine Sample

Please complete the laboratory label attached to the collection bottle to include patientís name, collection start time and date and collection end time and date.
Test Schedule: As required
Turnaround time from when specimen
is received in testing laboratory:
24 hours
Reference Range: 24 hour urine:
2.50-8.50 mmol/24h
Effective Date: 2011-01-24
Revised Date: 2019-02-21
Critical Value:  
Interpretive Comments: Useful to confirm suspected urinary magnesium loss, evaluate magnesium metabolism, abnromal serum magnesium concentrations, electrolyte status and in the workup of nephrolithiasis.

Urinary excretion of magnesium is diet dependent.

Low urine magnesium:
In states of hypomagnesaemia decreased urinary magnesium indicates a non-renal cause:
decreased dietary magnesium (malabsorption, acute and chronic alcoholism, long-term parenteral therapy), dehydration and volume depletion, diabetic acidosis, hypocalcaemia, Addison's disease, hypothyroidism, and hyperparathyroidism.

High urine magnesium:
Chronic glomerulonephritis, aldosteronism, Bartter's syndrome, and drug therapy (corticosteroids, cyclosporine, thiazide diuretics).
Special Processing:  
Comments: Reference Ranges are based on Non-Occupationally exposed population.
Method of Analysis: Colorimetric end point
Critical Information Required:  
Storage & Shipment:  
System Codes: 
Referred To:  

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