The total and ionized calcium in blood serum
Reference values of total calcium concentration in blood serum - 2,15-2,5 mmol / L or mg 8,6-10%;ionized calcium - 1,15-1,27 mmol / l.Physiological calcium
value is to reduce the ability to bind water tissue colloids, reducing the permeability of tissue membranes participation in building skeleton and hemostasis system, as well as neuromuscular activity.It has the ability to accumulate in various areas of tissue damage pathological processes.Approximately 99% of the calcium in bones is, the rest - mainly in the extracellular fluid (almost exclusively in the serum).Approximately half of serum ionized calcium is circulated in the (free) form, the other half - in the complex, preferably with albumin (40%) in the form of salts - phosphate, citrate (9%).Change of albumin in blood serum, especially hypo-albuminemia affects the total calcium concentration without affecting the clinically more important indicator - the concentration of ionized calcium.It is possible to calculate the "corrected" total calcium
regulate calcium metabolism parathyroid hormone (PTH), kal-tsitonin and derivatives of vitamin D. PTH increases the concentration of calcium in blood serum, increasing its elution from the bone reabsorption in the kidney and stimulates their conversion to vitamin D to its active metabolite, calcitriol.PTH also increases renal phosphate excretion.The level of calcium in the blood regulates PTH secretion by negative feedback mechanism: hypocalcemia stimulates and inhibits the release of PTH, hypercalcemia.Calcitonin - a physiological antagonist of PTH, it stimulates calcium excretion by the kidneys.vitamin D metabolites stimulate absorption of calcium and phosphate in the gut.
calcium content in blood serum changes with dysfunction pas raschitovidnyh and thyroid glands, tumors of various localization, especially with metastasis to the bone, renal failure.Secondary calcium involvement in the pathological process takes place in the digestive tract pathology.Often, hypo- and hypercalcemia can be the primary manifestation of the disease process.