Magnesium is an important element from the alkaline earth group, which is counted among the electrolytes (blood salts).Thereby, magnesium as an anion is mainly intracellular (inside the body cells) and is found to a large extent in the bone (60%), circa 40% is found in the skeletal muscles, one third of the free magnesium (1%) is bound to protein.Only one percent is found in the extracellular space (space outside the cells). The total magnesium content of the human body is circa 50 g.The daily requirement is 360-480 mg.It is mainly needed for acid-base and electrolyte (salt)-water balance, as well as for normal nerve and muscle function.
The procedure
Material needed
- Blood serum → rapid processing (centrifuge within 2 h of collection).
- Or LiH plasma, spontaneous or collected urine (24 h urine).
Preparation of the patient
- Not necessary
Disruptive factors
- Incorrectly high values in hemolysis (blood failure).
Normal values – blood
| Standard values in mmol/l | |
| Newborn | 0,48-1,05 |
| Children | 0,60-0,95 |
| Women | 0,77-1,03 |
| Men | 0,73-1,06 |
Normal values – urine
| Normal values in mmol/24 h | 2,05-8,22 |
Indications
- Suspected disturbances in magnesium balance
Interpretation
Interpretation of elevated values (in serum; hypermagnesemia (magnesium excess)).
- Familial hypocalciuric hypercalcemia (calcium excess) – congenital form of excessive blood calcium levels.
- Hypothermia (hypothermia)
- Hypothyroidism (hypothyroidism)
- Adrenal insufficiency
- Renal insufficiency (kidney weakness), acute and chronic.
- Shock
- Sepsis (“blood poisoning”)
- Strongly exaggerated magnesium intake
- Trauma (injuries)
- Burns
- Condition after cardiac arrest
- Taking laxatives (laxatives) such as lactulose.
Interpretation of decreased values (in serum; hypomagnesemia (magnesium deficiency)).
- Alimentary (nutritional)
- Decreased intake, for example malnutrition due to alcoholism.
- Fasting
- Parenteral nutrition without adequate magnesium substitution
- Endocrinological causes
- Primary or secondary hyperaldosteronism – excessive blood levels of aldosterone; this is mainly needed for fluid regulation.
- Hyperparathyroidism, primary and secondary – parathyroid hyperfunction.
- Hypoparathyroidism (parathyroid hypofunction).
- Hyperthyroidism (hyperthyroidism)
- Condition after parathyroidectomy (parathyroidectomy).
- Metabolic (metabolic) disorders.
- Diseases
- Renal losses in, for example, interstitial kidney disease, tubular defect, renal tubular acidosis, diabetic ketoacidosis, alcoholism (inhibition of tubular reabsorption), Bartter syndrome or Gitelman syndrome (GS).
- Intestinal losses and absorption disorders due to gastric juice loss during vomiting, acute and chronic diarrhea (diarrhea) and exocrine pancreatic insufficiency (pancreas weakness) e.g. due topancreatitis (pancreatitis).
- Poorly adjusted diabetes mellitus (diabetes).
- Metastases (daughter tumors) from malignant (malignant) tumors.
- Burns
- During recovery after kwashiorkor and protein-energy malnutrition.
- Medication
- Renal losses (kidney dysfunction) due to loop diuretics (dehydrating medications) such as furosemide or thiazide diuretics such as hydrochlorothiazide (HCT).
- Tubule damage by aminoglycosides, ciclosporin (cyclosporin A), cisplatin,
- Laxative abuse (laxative abuse).
- For other medications, see “Hypomagnesemia due to medications.”
- Increased demand
Further notes
- The magnesium serum level gives the total magnesium content only very inaccurately.
- Because the clinical symptoms of hypocalcemia (calcium deficiency) and hypomagnesemia (magnesium deficiency) are similar, it is useful to determine both parameters simultaneously (hypomagnesemia (magnesium deficiency) may be the cause of hypocalcemia (calcium deficiency)).
- The normal requirement of magnesium is 300 mg/d in women and 350 mg/d in men.
Attention!Note on the supply status (National Consumption Study II 2008)In the age group of 19-80 LJ. only 62-78% of women and only 59-82% men reach the intake recommendation. The worst supplied men and women >25th year lack about 100 mg magnesium. The poorest supplied men and women (DGE recommendations: m. 19th-24th LJ 400 mg/day, m. 25th-80th LJ. 350 mg/day, w. 19th-24th LY 310 mg/day, w. >25th LY. 300 mg/day)