Disorders of calcium metabolism

Calcium is an abundant mineral and has diffuse cellular functions in bone metabolism, cell division, coagulation, enzyme regulation, glycogen metabolism, muscle contraction, neurotransmission, protein synthesis, and degradation. Calcium is ingested in the diet and absorbed in the small intestine. It is distributed throughout the body, but 99% appears in the bone [1–3]. Adult humans contain more than 1 kg of calcium, of which over 99% is skeletal and dental and only 0.1% is in extracellular fluids. About half the calcium in serum is bound to protein, primarily of which is albumin. Decreases in serum albumin are accompanied by decreases in calcium (a drop of 1 g/dL of albumin lowers the calcium by about 0.8 mg/dL). Several calcium determinations and measurement of ionized (physiologically active) calcium levels may be needed to accurately assess calcium status..