Ionized calcium or Total calcium? - Osteoporosis Message Board

osteoblast · 03-20-2007, 03:59 PM

I know there has been some discussion regarding the two blood calcium tests-total calcium and ionized calcium. I wrote a few weeks back that my dr. had ordered on two occasions the total calcium tests when there was concern about elevated calcium . Both total calcium tests came back slightly out of range on the high side. Another dr. I was seeing ordered an ionized calcium-which came back in range.

I was trying to get clarity about which is the most reliable test. The first dr. said it was the total not the ionized. The second said it was absolutely the ionized. Another poster here ( Lewis) stated it was the ionized and cited to dr. norman's parathyroid website. I looked there and he clearly states the ionized as the preferred. Also other checking around labtest sites on the net appear to say it is the ionized.

Has anyone else looked at this?

DesertBloom · 03-20-2007, 06:27 PM

Hi Osteoblast: Most Dr's run total calcium and feel that's sufficient, but then there are others that use ion cal test's to determine specific problems, so they feel they are more accurate, so you'll have to decide, based on your individual symptoms. Ionized cal measures the *free* calcium in your body and not the bound. Below is a link that explains it but it's a more than a couple of pages long. My Drs feel that the ionized test gives more info since they are looking for specific problems that a total cal *may* not show, even if it is elevated or not. My total cal is always normal and my ion cal is always elevated, so that just gives you an idea on how different the results can be. Also included in the link below is the reference ranges for total cal and ion cal which are very different.

[url]http://www.labtestsonline.org/understanding/analytes/calcium/test.html[/url]

Good Luck...

osteoblast · 03-20-2007, 07:04 PM

Thank you DesertBloom. You confirmed what was becoming clear to me. I am also baffled by the advice I received about cutting back my calcium intake , after the dr. reviewed the high total calcium reading. Do you know how that works? Unfortunately I have a non-verbal dr. and the last time I called the dr. I was asked by her asst. "the dr. wants to know what is your one question?" Well, it's not always so tidy that one question will do! Anyway I had to make a choice and the cal supplement question could not be asked. I need a new dr. that wants to communicate.

DesertBloom · 03-21-2007, 09:37 AM

Hi Osteoblast: Boy, I don't know if I could handle a Dr that only allows one question, although I've had a few like that years ago. Could you possibly find someone else?

I'm not sure what your question is, are you asking about how calcium is used by the body?

I've always been told that ionized Ca is more important, but who knows...

Here's another link that explains the test, and it's uses.

[url]http://www.nlm.nih.gov/medlineplus/ency/article/003486.htm

[/url]

osteoblast · 03-21-2007, 09:56 AM

Hi DesertBloom: Yes, it was the one question comment that told me clearly that the dr. was not right for me.

On the question, I will try to be more clear and I will check the site you provided. When you have been diagnosed with high blood calcium, why does
the dr. advise you to cut your calcium supplement intake? What is the mechanism that they are seeking to alter? Specifically, can you expect to lower the blood calcium level by lowering supplemental calcium intake?