Measurement of magnesium levels (Mg) is used as an indicator for the body's metabolic activity (such as carbohydrate metabolism, protein synthesis, nucleic acid synthesis, muscle tissue contraction) and kidney function because 95% of magnesium is filtered through glomerulus is reabsorbed into the renal tubes. Measurement of serum magnesium levels is useful in monitoring preeclampsia patients treated with magnesium sulfate.
Most of the body's magnesium, which is 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 the activity of many enzymes, and has a significant effect on calcium metabolism. Magnesium along with potassium is the most important intracellular cations.
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.
The concentration of magnesium in the serum provides only an approximate estimate of magnesium adequacy or deficiency. Hypomagnesemia indicates a sufficient lack of magnesium, but the absence of hypomagnesemia cannot rule out significant magnesium deficiency. Serum magnesium concentration is not associated with any magnesium ion reservoir except interstitial fluid.
Possible Interpretations of Pathological Values
- Increase (Hypermagnesaemia): Addison's disease, ataxia, severe dehydration, diabetes (uncontrolled diabetes, diabetic acidosis, controlled diabetes in elderly patients), arrhythmias, hypercalcemia, leukemia, hypothyroidism, hypophosphatemia, nephrolithiasis, leukemia (lymphocytic and myelocytic), mood disorders, parenteral nutrition, kidney failure or kidney damage. Medications: Magnesium-containing antacids, calcium-containing drugs, laxatives, thyroid medicines.
- Decrease (Hypomagnesaemia): Acute tubular necrosis (diuretic phase), chronic alcoholism, aldosteronism, Bartter's syndrome, complications of colon resection, convulsions, diabetic ketoacidosis, chronic diarrhea, arrhythmia, excessive breastfeeding, excessive sweating, hepatitis, cirrhosis of the liver, hepatic impairment, hypokalaemia, hypercalcaemia, hyperthyroidism, hypoparathyroidism, intravenous magnesium-free solutions, ketoacidosis, kwashiorkor (severe malnutrition), laxative abuse, tetany syndrome with magnesium deficiency, pancreatitis (chronic, acute), phosphate depletion, postoperative, primary hyperaldosteronism, prolonged gastric drainage, decreased magnesium uptake, decreased magnesium uptake (specific magnesium malabsorption), phosphate depletion, postoperative, primary hyperaldosteronism, prolonged gastric drainage, reduced magnesium intake, reduced magnesium absorption (specific malabsorption of magnesium, generalized malabsorption syndrome, excessive resection of the large intestine, diffuse bowel disease or injury), kidney disease (chronic), renal impairment of magnesium absorption, kidney transplantation, renal tubular acidosis, stress with excess catecholamines, tetanus, gestational toxemia, ulcerative colitis, increased extracellular fluid volume. Medications: Alcohol, amphotericin B, some antibiotics (neomycin, aminoglycosides), calcium gluconate, cisplatin, citrate, corticosteroids, cyclosporin A, diuretics (loop, thiazides, such as furosemide, ethacrynic acid, hydrochlorothiazide), gentamicin, glucose, laxatives, insulin, mannitol, urea.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of 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 in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal 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 we contact your doctor to get the best possible medical care.