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Test Code MAGU Magnesium, 24 Hour, Urine

Useful For

Assessing the cause of abnormal serum magnesium concentrations

 

Determining whether nutritional magnesium loads are adequate

 

Calculating urinary calcium oxalate and calcium phosphate supersaturation and assessing kidney stone risk

Method Name

Colorimetric Endpoint Assay

Reporting Name

Magnesium, 24 Hr, U

Specimen Type

Urine


Specimen Required


Collection Container/Tube: 24-hour graduated urine container with no metal cap or glued insert

Submission Container/Tube: Plastic, 5-mL tube (T465) or a clean, plastic urine container with no metal cap or glued insert

Specimen Volume: 4 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Refrigerate specimen within 4 hours of completion of 24-hour collection.

Additional Information:

1. 24-Hour volume is required.

2. See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.


Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

51-269 mg/24 hr

Reference values have not been established for patients <18 years and >83 years of age.

Reference values apply to 24-hour collections.

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer’s instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83735

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MAGU Magnesium, 24 Hr, U 24447-5

 

Result ID Test Result Name Result LOINC Value
MG24 Magnesium, 24 Hr, U 24447-5
TM115 Collection Duration 13362-9
VL111 Urine Volume 3167-4
MGCN Magnesium Concentration 32024-2

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.

Ambient

OK

Refrigerate

Preferred

Frozen

OK

50% Acetic Acid

OK

Boric Acid

OK

Diazolidinyl Urea

OK

6M Hydrochloric Acid

OK

6M Nitric Acid

OK

Sodium Carbonate

No

Thymol

OK

Toluene

No

Forms

If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.