@njx58 my former rheum (currently in search of a new one, as they are no longer in my insurance network) does not use bone markers to guide clinical treatment. But I had them done anyway on my own, first as a baseline before treatment with Forteo and then after 2 or 3 months (I don't remember which off the top of my head) and the second test did show it was working. I haven't had the tests repeated since. I'm now 16 months in. I'm having a DEXA in March or April.