Calcium Protein Binding (CALCIUM)
Calcium in plasma is in two main forms: as free ions and as calcium bound to plasma proteins. It is the level of free calcium ions that is important in the regulation of neuromuscular irritability and other cellular functions; the protein-bound fraction is biologically inert. In plasma, in normal adults, the reference range of total plasma calcium concentration is about 8.8 to 10.4mg/dl. However, hyperproteinemia (eg, due to hyperglobulinemia in myelomatosis) can increase total plasma calcium without changing ionized calcium levels, and hypoalbuminemia (eg, due to liver cirrhosis or nephritis) can decrease plasma calcium while keeping ionized calcium normal. Consequently, in examining a total plasma calcium concentration it is helpful to also know the percent of protein-bound calcium so that free ionized calcium can be determined by subtracting protein-bound from total calcium.
KeywordsAlbumin Nephritis Doyle
Unable to display preview. Download preview PDF.
- 1.Petersdorf, RG, et al: Harrison’s Principles of Internal Medicine, ed 10. New York, McGraw-Hill Book Co, 1983, p 1923.Google Scholar