Sign in →

Test Code URMG Urine Magnesium, Timed

Important Note

If ordering a random collection, use order code RMG. 

Specimen and Container/Tube

Specimen Type: Urine, 24 Hour Timed Collection

Preferred Specimen:  24 Hour Sterile Plastic Container

Other Acceptable specimens: Sterile Clean Glass Container

Specimen Stability

Storage Temperature

Stability

Room temperature

3 days 

Refrigerated

3 days

Frozen

1 year

Collection Instructions

  • Provide 24-hour urine collection instructions and container to patient.
  • Collect specimen per standard laboratory collection procedures. 
  • No preservatives or additives.
  • Keep 24 hour urine refrigerated during collection process. 

Specimen Handling and Transport Instructions

UCMC Onsite Instructions: 

  • Collect specimen per standard collection procedure and send to laboratory immediately.
  • No preservatives or additives.

UCMC Offsite and UC MedLab Outreach Instructions: 

  • Samples should be centrifuged within 2 hours of collection
  • No preservatives or additives
  • Aliquot 10.0 mL of well mixed urine into plastic tube. 
  • Urine samples must then be sent refrigerated at 2-8oC.

Rejection Criteria

  • Common specimen rejected situations include: incorrect specimen type, insufficient volume, missing or incomplete specimen identifiers, incorrect specimen transport, or specimens outside stability limits. 
  • Specimens that are collected with preservatives or additives.

Reference Values

 

Test

Age

Sex

Reference Range

Urine Magnesium Timed

All

All

12.0 - 291.0 mg/24hr 

Critical Values

Not applicable

Turnaround Time

Turnaround times are relative to the time the specimen is received in the test laboratory. 

STAT Turnaround Time: 1 hour

Routine Turnaround Time: 4 hours

Testing Schedule: 24/7

Clinical Indications

Urinary collection is valuable to detect magnesium deficiencydue to gastrointestinal causes (eg, gut failure or Crohn’s disease).

Test Components

Urine collection duration, Urine total volume, Urine magnesium random, Urine magnesium timed 

CPT Codes

83735

LOINC Codes

19124-7

Methodology

Spectrophotometric, Colorimetric Endpoint Method (Roche Diagnostics)

Synonyms/Keyword Search

24 hour urine magnesium 

Last Review Date

4/7/2025

Volume

Preferred Volume: 10.0 mL

Minimum Volume: 1.0 mL