Urine magnesium levels are measured to evaluate pathological concentrations of serum magnesium, determine the adequacy of magnesium uptake, and assess the risk of kidney stones (along with determining other factors).
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Measurement of magnesium (Mg) levels is used as an indicator for the body's metabolic activity (such as carbohydrate metabolism, protein synthesis, nucleic acid synthesis, and muscle tissue contraction) and kidney function because 95% of magnesium which is filtered through the glomerulus is reabsorbed into the renal tubes. Most of the body's magnesium, an electrolyte, is concentrated in the bones, cartilage, and cells. In addition, magnesium is essential in the blood clotting mechanism. Magnesium regulates neuromuscular stimulation, acts as a cofactor that modifies many enzymes' activity, and significantly affects calcium metabolism. Magnesium, along with potassium, is the most essential intracellular cation.
Symptoms of hypermagnesemia include lethargy, drowsiness, flushing, nausea, vomiting, speech disorders, hypotension, weakness or absence of tendon reflexes, and changes in electrocardiogram (such as prolongation of PR and QT interval, wide QRS, bradycardia), respiratory depression.
Magnesium-rich foods include seafood, meats, green vegetables, whole grains, and nuts. Excessive phosphate intake prevents the absorption of both magnesium and calcium.
Urine magnesium testing is helpful in evaluating kidney disease and magnesium deficiency. In magnesium deficiency, urine magnesium decreases before serum magnesium.
Magnesium is an inhibitor of the growth of calcium crystals in the urine and contributes to the supersaturation of calcium oxalate and calcium phosphate. However, low magnesium in the urine is not considered a cause of kidney stones, nor is supplementation of magnesium an effective treatment to prevent kidney stone formation.
Possible Interpretations of Pathological Values
- Increase: Alcoholism, Bartter's syndrome, hypermagnesemia, nephrolithiasis. Medications: Aldosterone, cisplatin, corticosteroids, diuretics (ethacrynic acid), thiazides
- Decrease: Kidney disease, kidney stones, magnesium deficiency, osteoporosis, syndrome of inappropriate secretion of antidiuretic hormone
Important Note
Laboratory test results are crucial for diagnosing and monitoring all pathological conditions. 70% and 80% of diagnostic decisions are based on laboratory tests. Correctly interpreting laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted based on each case and family history, clinical findings, and the results of other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
