Those of you on Entyvio may be interested in this experience with measuring Entyvio levels in the blood.
I was taking Entyvio via infusion every 8 weeks (300 mg). My gastroenterologist recommended I get tested for trough Entyvio levels in my blood, right before an infusion. We used the "Prometheus Anser VDZ" test, which reported 13 ug/mL.
Based on that result (considered low), we increased the infusion frequency to every 8 weeks. After several cycles, the Prometheus Anser VDZ test reported 13.7 ug/mL.
I wrote to Prometheus, requesting information on the reproducibility of the test, that is, what's the error bar? Is 13.7 significantly different that 13.0? They refused to answer me, and also did not provide an answer to my doctor.
But, based on the still low result, we increased the infusion frequency to every 4 weeks. After several cycles we ran the test again.
This time, Prometheus, reported two things:
1. My Entyvio level was now over 40 ug/mL.
2. They had changed the test methodology, and my previous result of 13.7 was now changed to 26 ug/mL.
Because both 26 and 40 ug/mL are considered high enough to cause risk of infection, we're back to 8 week infusions.
I called Prometheus. The rep told me that results over a specific period of time had been effected by a calibration error. He said notification had been sent to the offices of all doctor's who ordered the test during that period. Notification was sent by fax, and the only confirmation that the message was received was that the fax machine acknowledged receipt of fax.
The Prometheus rep would provide nothing to me in writing.
It appears that fax did not reach my doctor, or somehow he missed it. We only became aware of this information in response to another test. If we had not changed from 6 to 4 weeks and retested, then I would still think my Entyvio trough level was 13.7 (low) instead of 26 (too high).
As far as I know, Prometheus is the only lab that measured Entyio levels in the blood.
I could find no information on Prometheus website about
any reason to question prior results. But if you have had your Entyvio levels measured this way, I suggest you ask if the results you have received are still considered valid.
Post Edited (Casey_LB) : 12/23/2019 3:41:10 PM (GMT-7)