calcium (calculation of concentration)

Last reviewed 01/2018

Corrected calcium concentration estimates the total concentration as if the albumin concentration was normal - usually taken as 40 g/l. A typical correction is that for every 1 g/l that the albumin concentration is below this mean, the calcium concentration is 0.02 mmol/l below what it would be if the albumin concentration was normal; i.e.

corrected [Ca] = measured [Ca] + {(40 - [albumin]) * 0.02}

However, in interpreting values adequate consideration must be paid to other factors which may affect albumin binding, for example, other proteins in myeloma, individual variation, cirrhosis.