MAGNESIUM, URINE

Message

"The test request form must state 24-hour collection volume. After collection, pH is adjusted to 1.5-2.0 with 6N HCl.
"

Test Code

3400

Alias/See Also

Mg, Urine

CPT Codes
83735

Preferred Specimen

"Urine (24-hour)
5 mL"

Minimum Volume

2.2 mL

Instructions

"Instruct the patient to void at 8 AM and discard the specimen. Then collect all urine including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning). Screw the lid on securely. Transport the specimen promptly to the laboratory. Container must be labeled with patient's full name, room number, date and time collection started, and date and time collection finished.
"

Transport Container

"Plastic urine container with 10 mL 6N HCl
"

Transport Temperature

"Refrigerate (KBS tablet is acceptable).
"

Specimen Stability

"
Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3
"

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

"No preservative in the collection container; presence of blood in the urine; improper labeling
"

Methodology
"Atomic absorption spectrometry (AAS) or colorimetric "

Reference Range

"Environmental exposure: 12.0-293.0 mg/24 hours
"

Clinical Significance

"Magnesium excretion controls magnesium balance.1 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.2 Renal conservation of magnesium is diminished by hypercalciuria, salt-losing conditions, and the syndrome of inappropriate secretion of antidiuretic hormone.1 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.
Hypercalcemia, hypophosphatemia and acidosis are among inhibitors of tubular reabsorption of magnesium
"

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.