@fireweed4286 , thanks for sharing these info! It is interesting to see what other endos do in terms of labs to figure out possible secondary causes. I read an article containing a "complete list" (maybe close to complete) for the causes and corresponding tests/labs but could not find it anymore. Some disease states could become a secondary cause for bone loss such as thyroid problems, gastrointestinal problems (celiac, ibs etc), etc. Certain prescription drug uses in the past or at present could be a cause too. In some, inadequate or improper nutrition could be a cause. Genetics could play a part... In any case, bone loss in postmenopausal women almost always has a component of estrogen difficiency.

It is interesting CTX and P1NP are commonly used in therapy monitoring, and as you pointed out, they are recommended by IOF. These two are not used as tools in diagnostics. Both Alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BSAP), on the other hand, could be used in diagnosis of certain bone disorders or assessing metabolic bone diseases, among other clinical uses. I think your endo was getting them tested to rule out these.

BSAP are also used by some endos to monitor bone formation during therapy, but we hear P1NP has become more commonly used nowadays.

It is interesting to note that bone-specific alkaline phospatase (BSAP) is a component of total alkaline phosphatase (ALP). The latter is included in CMP, complete metabolic panel. As a matter of fact, if the bone forming signal is strong enough while on an anabolic, we could see an uptick of ALP without even getting BSAP tested. I saw my total ALP almost doubled (above upper limit of normal range) during peak Forteo effect. In general, ALP is not a specific or sensitive indicator for bone formation compared to BSAP. I read that P1NP and BSAP measure different stages of bone formation and that P1NP is a more sensitive and dynamic indicator.