The ionized calcium has been low 2 times within 8 months and the cbc calcium is trending higher than my norm

The last tests were

Ionized 1.07 1.12-1.32

cbc 9.2 8.3-10.5

I know they are not seriously out of range but there is a trend I'm concerned about because of the low gfr. I think 59

My b-12 levels have sat over 1800 but I haven't taken it in a year almost because I think the levels are high and wanted to see if they lowered

I take calcium citrate regularly

I think a pth level test next?

Thanks for taking a look