Calcium total

Calcium is one of the main trace elements that is necessary for human life. Such importance of the mineral is due to the functions it performs:

• Nerve and muscle impulse transmission;
• Blood coagulation processes;
• Heart muscle work;
• Formation of cellular action potential on cell membranes;
• Production and activation of a huge number of enzymes involved in almost all biologically significant processes of the whole organism;
• Formation of bone density.

With an imbalance of calcium, all of the above functions are disrupted. The determination of calcium in urine is necessary to identify the cause of its reduced or increased content in the blood, which is directly related to the functional state of the kidneys. Normally, the amount of calcium absorbed into the body corresponds to its excretion by the kidneys. After the trace element is filtered into the primary urine, 87-98% of calcium is reabsorbed (absorbed) back into the blood. Reabsorption is enhanced by parathormone.

In various diseases (especially kidney) there are several mechanisms that lead to calcium imbalance:

• Intake of insufficient amount of calcium from food: decrease of trace element in blood and urine;
• Decrease in reabsorption: calcium level in urine increases, in blood - decreases (hypocalcemia);
• Decrease in filtration from bloodstream to kidneys: increase in blood calcium levels and decrease in urine;
• Increase in phosphorus, which is an antagonist ("opponent") of calcium, resulting in a decrease in calcium concentration in both blood and urine;
• Increased destruction of cells (e.g., bone tissue) leads to the release of calcium from them, as a consequence, the mineral becomes more in both blood (hypercalcemia) and urine.

There are 3 types of absorptive hypercalcemia (i.e., when the increase in calcium is due to increased absorption in the intestine):

• Type I: an innate intestinal trait characterized by increased sensitivity to calcitriol (activates calcium absorption);
• Type II: increased blood calcitriol concentration;
• Type III: increased blood calcitriol concentration due to phosphorus deficiency.

Also distinguished is kidney hypercalciuria (KH), which is due to primary loss of calcium through the kidneys.