Why is the CTX test chosen over the NTx test for evaluation of risk for BONJ?

I have a patient who has been on Actonel [risedronate] for 10+ years and I requested a CTX test for him to determine risk prior to implant surgery. His doctor ordered a NTx urine test instead and said it was basically the same. Most studies and postings I found always refer to the CTX test. What is the difference between the two other than they cleave different sections on the peptide? Â Is one more accurate than the other and how so?

6 Comments on Why is the CTX test chosen over the NTx test for evaluation of risk for BONJ?

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Harry Karna DDS
7/31/2012
http://en.wikipedia.org/wiki/C-terminal_telopeptide
dr. bob
8/1/2012
Do not know but will follow the post. Thanks for posting it.
Dr. dan
8/1/2012
My understanding of the whole subject in this regard is that the CTX test is the best out there. However, still not the greatest diagnostic indicator of ORN. Oral bisphosphanates, from what I have heard from some experts, are highly unlikely to cause ORN. That, in fact, coupled with bacterial infections there is much much higher risk of it happening. I hope I got that right. In my opinion, I would consult with the physician who is taking care of your patient and giving the actonel. Is it ok for her to go on a vacation without those meds? Does he/she feel there is a risk to do surgical treatment while on those meds?
Baker k. Vinci
8/5/2012
Dr. Dan, the companies quote a 1: 1,000, 000 chance of getting bronj, with oral meds. I'm going to predict, that when "it" is all figured out, they will realize they are wrong. I now have 14 cases of "bronj" from oral use. Baton Rouge is not a big town and with 6 other active surgeons, I can't be getting it all. I'm embarrassed to say, I know nothing of either of these test! Bv
Greg Steiner
8/6/2012
Hello Baker How are you treating these patients and what are your outcomes? Have you ever seen bronj in bone that was grafted? Thanks Greg Steiner Steiner Laboratories
Carlos Boudet, DDS
8/15/2012
You should give the information posted by Dr. Karna to the physician. If any testing is done, it should be the CTX test, as urine NTX is not reliable for measuring the effects of biphosphonates on osteoclastic activity and bone turnover. I have found that when I explain the risk of bisphosphonate-associated osteonecrosis of the jaw to the patient, they tend to follow my recommendations. Good luck!

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