If doctor in health tap able to order bone density test (dexa scan) in san francisco?

Not from this site. This is the HT Public information site where volunteer docs across the country answer health questions. It does not offer direct patient care and does not share your post with other sites that do. You can access a pay site at www.connect@healthtap.com to see if one of their docs will take your case in consultation. Fees are due whether they order anything or not.

Possible on the paid HealthTap section. The most important following the test would be how to make sense of the result and previous such tests will be needed for review, current treatment and symptoms and previously diagnosed conditions, such as fractures as well as clear goals going forward. Otherwise it will be a shortcut to nowhere.