Calcium is a major mineral component of bone. 99% of the calcium in the body is in the bones and teeth, which is a huge reservoir for maintaining serum calcium levels, and the rest is distributed in body fluids and soft tissue. Calcium ions play an important role in transmitting nerve impulses, muscle contraction, heart function and coagulation processes.

Hormonal regulation of the calcium metabolism and that of phosphorus is complex. Mutual relations between the small intestine, skeleton, kidneys and endocrine system, particularly parathyroid, maintain homeostasis of calcium and phosphorus. Also, calcitonin, vitamin D, estrogens and androgens are the factors that influence calcium levels. The amount of protein in the blood affects the level of calcium, since 45% of the calcium in serum is protein-bound. This lowers serum albumin decreased total serum calcium.

Serum calcium concentrations may indicate abnormal parathyroid dysfunction, bone diseases, carcinoma, malnutrition and malabsorption syndrome, deficiency of vitamin D and kidney disease. 90% of hypercalcemia cases occur in the context of hyperparathyroidism, as paraneoplastic manifestation or granulomatous disease. Hypercalcemia in the sarcoidosis, adrenal failure and hyperthyroidism is usually detected in a clinical setting suggestive of the diagnosis.

Recommendations for serum  calcium tests :

• every two years in patients older than 50 years for osteoporosis screening (with measurement of height and weight); • in tetany (type investigation hypocalcemia); • spontaneous fractures, bone pain, bone radiological changes, growth disorders, dental alterations; • nephro- or urolithiasis, nephrocalcinosis, polyuria, polydipsia, chronic kidney disease; • acute pancreatitis, gallstones, diarrhea recurrence, malabsorption; • Post-surgical in case of thyroidectomy and parathyroidectomy, in hyperparathyroidism, thyroid disease, testicular, ovarian, adrenal; • granulomatous disease; • tumors;

• adverse reactions to certain medications: vitamin D, A, anticonvulsants, corticosteroids, thiazide Digital.

Reference values

Age Stock mg / dL

2-12 Monday, 4.8 – 10.8

1 – 4 years 8.4 – 10.4

5 – 20 years 9.2 – 11

> 20 years 8.6 – 10.2