Magnesium
Use
Magnesium deficiency produces neuromuscular disorders. It may cause weakness, tremors, tetany, and convulsions. Hypomagnesemia is associated with hypocalcemia, hypokalemia, long-term hyperalimentation, intravenous therapy, diabetes mellitus, especially during treatment of ketoacidosis; alcoholism and other types of malnutrition; malabsorption; hyperparathyroidism; dialysis; pregnancy; and hyperaldosteronism. Renal loss of magnesium occurs with cis-platinum therapy. Alfrey also adds amphotericin toxicity to the causes of hypomagnesemia.
Special Instructions
Indications for measurement include the presence of unexplained hypocalcemia, instances where hypokalemia is unresponsive to potassium supplementation, and cardiac disorders such as congestive failure, ventricular ectopy, and digitalis use. Serum magnesium is selectively indicated for patients on high-dose diuretics and those on certain antibiotic therapies. The test requires separating serum or plasma from cells within 45 minutes of collection.
Limitations
Hemolysis can lead to falsely elevated results as magnesium levels in erythrocytes are higher than in serum. Bilirubin may cause falsely low values. Serum magnesium testing may not predict the body's magnesium status accurately due to variations in total body stores.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 19123-9
- 19123-9
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.7 mL
Container
Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube
Collection Instructions
Separate serum or plasma from cells within 45 minutes of collection.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
EDTA or citrate plasma specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
Other tests from different labs that may be relevant