@kristie2
Yes, kristie is bringing up a good point. When best to use serum bone labs (BTMs)?

What I am seeing is that they are exceptionally useful for managing the "cycling" of osteoporosis drugs and even continued use of these drugs. The results are helpful to know which drug to use and when.

Examples:
When you pause bisphosphonates (a "drug holiday"), BTMs like s-CTX (resorption) and P1NP (formation) help your doctor decide when to restart. A significant rise in these markers indicates bone loss is accelerating and therapy should resume.
Or...
Certain drugs, like Prolia, cannot simply be stopped; they must be followed by another agent (usually a bisphosphonate) to prevent a rapid rebound in bone loss. BTMs verify if the follow-up drug is successfully "catching" the bone before it weakens.
More...
Since oral bisphosphonates are notoriously hard to absorb, BTMs can confirm within 3 months if the drug is actually working or if you need to switch to an IV version.