The CTX Test

Having successfully petitioned the oncologist to suspend the Aredia (IV bisphosphonate) therapy, earlier this week I presented myself in the office of an oral surgeon, who concurred with the endodontist's diagnosis of external root resorption in tooth #27. If he is to perform an extraction, he insists (as the endodontist predicted he would) on a CTX test to gauge the risk of osteonecrosis of the jaw (ONJ) arising from the bisphosphonate therapy. Of course an oral surgeon has the power to write a prescription for this test, so he sent me home with such.

Ordinarily, if an MD gives you a script for a blood test, say for a lipid panel (cholesterol check), you just take it to a local outpost of LabCorp or Quest Diagnostics. After a little dance involving making copies of your medical insurance card and a photo ID, and signing a form agreeing to pay if the insurance company for some reason declines the honor of doing so, your blood is eventually drawn into one or more little tubes, and some days later the results are transmitted to the doctor's office. That's the basic business of these giants of the medical-industrial complex.

Things are a bit more complicated for a cancer patient. I once tried taking my monthly script to the nearest LapCorp site. Of the three people who happened to be working there at the time, only one claimed to have any idea what the script was talking about. He happened to have worked in a cancer clinic. He said, "Yes, I'm pretty sure we do that, but...". But the logistics surrounding getting the blood sample to the right test lab were such that I could be given no reliable ETA for when the results would reach the oncologist's office. No sale. Instead, although it's a longer drive, I always take this script to the lab in the cancer center; for them, this test is routine, and is reliably turned around within 48 hours.

The cancer center lab waved off the CTX test, which surprised me a little; but then, the oncologist had told me that he has no use for it in his practice. The oral surgeon was pretty sure that Quest could do the test, which I confirmed with a phone call to the nearest Quest site. However, when I arrived there, to my surprise, my insurance card was rejected; the test would be done only if I presented a credit card. So: One of the largest providers of medical diagnostics in the country won't play with one of the largest providers of medical insurance in the country. Love this system.

On the way home, I stopped at the LabCorp site. "I've worked here for seven years, and I've never heard of this test." A phone call to LabCorp customer service confirmed the technician's fear that he couldn't do the test.

My next thought was to discuss the situation with the medical insurance company. What would happen if I paid Quest to do the test and then submitted a claim? But before I did that, another question occurred to me: What if the CTX test really travels under a different name -- a more technical-sounding name that people preferred to abbreviate as CTX? A few moments with Google provided the answer: The CTX test is really the "C-telopeptide serum" test. There is an even longer, more technical-sounding name (the name from which "CTX" actually comes), but I took "C-telopeptide serum" to the test menu on the LabCorp web site and, lo and behold, there it was. Just to be certain, I verified with the oral surgeon's medical assistant that this really is the test I was supposed to get.

This morning, I journeyed back to LabCorp, this time armed with the LapCorp test number for "C-telopeptide serum", and was in and out of there in minutes. All I have to do now is wait for the oral surgeon's reaction to the results.