@serious from what ive read, your CTX level seemed reasonable after being on a bisphosphonate such as risedronate, although it could be a lot lower if fosamax or reclast is used. That being said, bear in mind that since risedronate is a weaker bisphosphonate and a shorter-acting one, your CTX might need to be monitored more frequently if you'd like to have an extended holiday. This could be a discussing point with your endo.