Calcium Levels and Health

Calcium (calcium) is an element from the group of alkali metals, which is counted among the electrolytes.Calcium is 98% skeletally bound, and only 2% of the total calcium is found in the extracellular space. Only about 50% of the total calcium in plasma or serum is present as free or ionized calcium. The ionized calcium is not affected by changes in albumin concentration. Approximately 45% of serum calcium is bound to albumin and about 5% is present as complex-bound calcium. Changes in albumin concentration affect total calcium. The biologically active fraction is the free calcium!Total body calcium is between one and two kilograms.Calcium incorporation into bone begins in the fetal period and continues into early adulthood, then decreases by one to two percent annually.Calcium is further important in mediating intracellular signaling and blood clotting.

The process

Material needed

  • Blood serum
  • 24 h urine

Preparation of the patient

  • Not necessary

Disruptive factors

  • Lithium-heparin tubesNote: EDTA tubes are not suitable for the determination of serum calcium, as they are complexed with calcium!
  • Muscle activity and venous congestion can increase calcium levels.
  • Keep urine cool.

Normal values – serum (blood)

Standard values in mmol/l
Newborn 1,75-2,70
Infants 2,05-2,70
Children 2,05-2,70
Adults 2,02-2,60

Normal values – urine

Gender Normal value in mmol/24 h
Women < 6,2
Men < 7,5

Indications

Interpretation

Interpretation of elevated values (in serum; hypercalcemia (calcium excess)).

  • Endocrinologic causes
    • Hyperparathyroidism, primary (pHPT)* and secondary (parathyroid hyperfunction) (pHPT approximately 25% of all cases of hypercalcemia).
    • Hyperthyroidism (hyperthyroidism).
    • Hypervitaminosis D (excessive intake of vitamin D).
    • NNR hypofunction (adrenocortical insufficiency) (adrenal insufficiency).
    • Estrogen deficiency
  • Metabolic (metabolic) causes.
    • Acidosis – overacidification of the blood.
    • Hyperproteinemia – increase in the protein content (protein) in the serum.
    • Hypophosphatemia (phosphate deficiency)
    • Hypophosphatasia
    • Milk alkali syndrome – metabolic disorder caused by calcium oversupply.
  • Malignant (malignant) diseases* (→ tumor hypercalcemia; tumor-induced hypercalcemia (calcium excess), TIH; tumor-associated hypercalcemia (calcium excess)) (TIH approximately 65% of all cases of hypercalcemia).
    • Malignant (malignant) (e.g., bronchial carcinoma, breast carcinoma, prostate carcinoma) or hematologic (affecting the blood cells) tumors (e.g., lymphoma, monoclonal gammopathy)
    • Osteolysis (bone dissolution) in bone tumors or metastases.
    • Osteolytic bone tumors such as plasmocytoma (multiple myeloma) – malignant disease in which there is an uncontrolled proliferation of specific cells (plasma cells).
    • Paraneoplastic syndrome – changes originating from a malignant tumor via hormonal control.
  • Tissue breakdown, mainly due to tumors.
  • Nephrolithiasis (kidney stones) – detectable by determination of calcium in the urine.
  • Sarcoidosis – inflammatory systemic disease affecting mainly the lungs, lymph nodes and skin.
  • Immobilization
  • Intoxications (poisoning) with aluminum
  • Medication
    • Thiazide diuretics (group of diuretic substances) such as hydrochlorothiazide (HCT).
    • Lithium
    • Vitamin A overdose
    • Vitamin D overdose
    • Vitamin D analogues

* Approximately 90% of all cases of hypercalcemia.

Interpretation of lowered values (in serum; hypocalcemia (calcium deficiency)).

  • Alimentary (nutritional)
    • Low intake of milk and dairy products – especially ovo-vegetarians and vegans.
    • High calcium losses – due to caffeine, high protein intake (protein intake), in chronic acidosis (hyperacidity).
    • High intake of oxalic acid-containing foods – beet, parsley, rhubarb, spinach, chard, nuts – and cereals with high phytate content (whole grain-rich diet), because both oxalate and phytic acid (phytate) inhibit calcium absorption by forming poorly soluble complexes.
    • Malabsorption / malnutrition
  • Endocrinological causes
  • Metabolic (metabolic) disorders.
    • Acidosis (renal-tubular) – leads to calcium loss.
    • Hypalbuminemia (protein deficiency) due toliver cirrhosis (liver shrinkage), nephrotic syndrome (collective term for symptoms that occur in various diseases of the glomerulus (renal corpuscles); symptoms are: Proteinuria (excretion of protein in the urine) with a protein loss of more than 1 g/m²/body surface per day; hypoproteinemia, peripheral edema due to hypalbuminemia of < 2.5 g/dl in serum, hyperlipoproteinemia – lipid metabolism disorder).
    • Acute hyperphosphatemia (phosphate excess).
    • Hypomagnesemia (magnesium deficiency) – inhibition of parathyroid hormone secretion, can lead to hypocalcemia in this way.
  • Vitamin D and calcium malabsorption (disruption of absorption).
    • Whipple’s disease (synonyms: Whipple disease, intestinal lipodystrophy; Engl : Whipplés disease) – rare systemic infectious disease; caused by the gram-positive rod bacterium Tropheryma whippelii (from the actinomycetes group), which can affect various other organ systems in addition to the obligately affected intestinal system and is a chronic recurrent disease; symptoms: Fever, arthralgia (joint pain), brain dysfunction, weight loss, diarrhea (diarrhea), abdominal pain (abdominal pain), and more.
    • Rickets (bone softening)
    • Celiac disease (gluten-induced enteropathy) – chronic disease of the mucosa of the small intestine (small intestinal mucosa), which is based on hypersensitivity to the grain protein gluten.
    • Zollinger-Ellison syndrome – usually malignant disease in which there are neoplasms that produce gastrin (hormone from the stomach).
  • Genetic diseases
    • Rare genetic defect of the calcium-sensitive receptor with a downward shift in the threshold for ionized calcium (autosomal dominant hypocalcemia) that causes functional hypoparathyroidism and may result in hypocalcemia
  • Malignant (malignant) diseases, such as osteoblastic metastases (hungry bones) – increased calcium incorporation in daughter tumors.
  • Other diseases
    • Renal insufficiency (kidney weakness) – decrease in intestinal calcium absorption, which may cause hypocalcemia – < 2.2 mmol/L; < 8.8 mg/dL
    • Osteodystrophia fibrosa – bone building disorders due to decreased storage of mineral salts.
    • Pancreatitis (inflammation of the pancreas).
  • Medication
  • Increased demand
    • Lactating women – during lactation (breastfeeding phase), 250 to 350 mg of calcium is delivered daily through the milk

Interpretation of elevated urine levels (hypercalciuria).

  • Endocrinological causes
    • Cushing’s syndrome – disease caused by an excess of glucocorticoids; can be detected by urinary calcium determination
    • Hypoparathyroidism, primary (parathyroid hypofunction) – parathyroid hormone deficiency.
    • Hyperthyroidism (overactive thyroid gland)
    • Estrogen deficiency
  • Malignant (malignant) diseases
  • Acidosis (renal-tubular) due tocalcium loss.
  • Immobilization (bone loss)
  • Milk-alkali syndrome (Burnett syndrome) – disorder of calcium metabolism caused by an alimentary oversupply of calcium with simultaneous intake of alkaline substances (eg, antacids).

Further notes

  • Average daily calcium intake is subject to very wide variations and can range from 10 to 50 mmol (400-2,000 mg/d).
  • The normal requirement for calcium in women as well as men is 1,000 mg/d.
  • Ionized calcium is freely filtered glomerularly (“affecting the glomeruli (of the kidney)”), but most (95-98%) is reabsorbed.

Attention!Note on the state of supply (National Consumption Study II 2008)In the age group of 19-80 LJ. only 35-48% of women and only 39-67% men reach the intake recommendation, with poorer intake with age. The worst supplied men and women lack about 500 mg calcium. (DGE recommendation 1,000 mg/day).