Magnesium, 24 hour urine

Alphabetical Test listing

Magnesium, 24 hour urine-994

Magnesium, 24 hour urine

Magnesium excretion controls magnesium balance. Magnesium urinary excretion is enhanced by increasing blood alcohol levels, diuretics, Bartter syndrome, corticosteroids, cis-platinum therapy and aldosterone. Renal magnesium wasting occurs in renal transplant recipients who are on cyclosporine and prednisone. Renal conservation of magnesium is diminished by hypercalciuria, salt-losing conditions, and the syndrome of inappropriate secretion of antidiuretic hormone. Magnesium deficiency is often inadequately documented by serum magnesium levels. Urinary magnesium analyses have been advocated before and after therapeutic magnesium administration to further investigate the significance of an apparent low serum magnesium.

Urine, 24 hour
5 mL aliquot of a 24 hour urine collection
2.2 mL aliquot of a 24 hour urine collection
  1. Measure and record the 24-hour total volume
  2. Mix well
  3. Transfer a 5 mL aliquot to a Transfer vial/tube with cap - 12mL (LabCorp)
  • Total volume

Ambient (preferred) - 14 days

Refrigerated - 14 days

Frozen - 14 days

Freeze/thaw cycles - Stable x3

  • No preservative in the collection container
  • Presence of blood in the urine
LabCorp Burlington (003400): R-NX
Mo - Fr
2 - 4 dats

Atomic absorption spectrometry (AAS) or colorimetric


Environmental exposure: 12.0 − 293.0 mg/24 hours