RT Book, Section A1 Kenigsberg, Lisa A1 Agarwal, Chhavi A2 Zaoutis, Lisa B. A2 Chiang, Vincent W. SR Print(0) ID 1146116429 T1 Disorders of Calcium Metabolism T2 Comprehensive Pediatric Hospital Medicine, 2e YR 2017 FD 2017 PB McGraw-Hill Education PP New York, NY SN 9780071829281 LK accesspediatrics.mhmedical.com/content.aspx?aid=1146116429 RD 2024/10/08 AB Calcium is the most abundant mineral in the body and is required for proper functioning of numerous intracellular and extracellular processes, including muscle contraction, nerve conduction, hormone release, and blood coagulation. Calcium also plays a unique role in intracellular signaling and is involved in the regulation of enzyme activity. Maintenance of calcium homeostasis is therefore critical. Ionized calcium, which is responsible for the physiologic effects, is maintained under normal conditions within a narrow normal range of approximately 4.5 to 5.3 ng/dL (1.12–1.32 mmol/L), with higher levels in neonates and infants.