Proper evaluation of serum calcium level requires estimation of:

Concentration of serum protein especially serum albumin is an impoant determinant of calcium ion concentration. Calcium is mostly bound to serum albumin. % of protein bound calcium = 0.8 x albumin (g/l) + 0.2 x globulin (gll) + 3. This formula is used for calculation of calcium bound to proteins. A rough formula is to add 1 mg/dl, to the serum calcium level for every l g/dl, by which serum albumin level is below 4 g/dL.