MAGNESIUM, 24 HOUR URINE WITH CREATININE

Specimen Required
After first morning void collect 24 hour urine with 25.0 mL 6N HCl, to maintain pH below 3. Last sample collected should be first morning void at the same time as the previous mornings first void. Mix urine well and send a 10.0 mL aliquot (1.0 mL minimum) refrigerated in a screw-capped urine cup. Record 24 hour volume on cup. Keep urine refrigerated during collection.

Alternate Specimen
Preservative may be added within 4 hours after collection is completed.

Methodology
Atomic Absorption Spectrometry

Stability
Room Temperature: 4 days; Refrigerated: 7 days; Frozen: 90 days

Reference Range
Magnesium, 24-Hour Urine
Adult Male:   28-180 mg/24 h  
Adult Female:   18-130 mg/24 h  
Magnesium, 24-Hour Urine
Adult Male:   16-90 mg/g creat  
Adult Female:   30-135 mg/g creat  
Creatinine, 24-hour Urine
3-8 years:   0.11-068 g/24 h  
9-12 years:   0.17-1.41 g/24 h  
13-17 years:   0.29-1.87 g/24 h  
Adult:   0.63-2.50 g/24 h  

Performed
Tuesday-Saturday

Turnaround Time3-6 days
Test CodeUMAGQ
CPT-4 Code (s)
83735, 82570
LOINC Codes
Magnesium, 24-hour urine   44336-6  
Creatinine, 24-hour urine   2162-6  
Magnesium, 24-hour urine   24447-5  
Total volume   3167-4  

Warde
Medical
Laboratory