--what are your albumin levels?

Much of the calcium in the blood is bound up in albumin. If your albumin levels are high--approaching 5--your total calcium levels may be reading as factitiously high compared to your ionized calcium levels.

The usual conversion factor is that for every tenth of an albumin point over 4.0, one must subtract .08 from the calcium level to get a true (or truer) actual total calcium reading. So, for instance, if one has an albumin level of 4.8 and a total calcium reading of 9.6, one should subtract .64 from that level (.8 times .8), giving an actual total calcium level of 8.96.

I deal with this quite often, as I tend to run high albumin levels (high protein, low carb diet), and my calcium levels need to be interpreted in light of that.