Heterophile (or Heterophilic) Antibody Interference with PSA Tests

I am looking for information about PSA tests which block heterophilic antibodies (which can cause artificial elevation of
PSA). I saw a post from member "WeightLoss" regarding trying to obtain Heterophilic Blocking Tubes from Scantibodies Laboratory in California (posted in July 2017) but could not find a follow-up to that post. I had a radical
prostatectomy in August at Vanderbilt. My Gleason score was 3 + 4. 85% of tumor was Gleason 3, and 15% was Gleason 4. My pathology report was good - clear margins and "organ confined" cancer. My surgeon, my nurse
practitioner, and the radiation oncologist that I recently saw were all very surprised that my post-surgical PSA is 2.7.
They all used the words "very unusual" to describe my post-surgical PSA. I believe I need PSA testing that blocks
heterophilic antibodies before I commit to radiation. (I want to be as sure as possible that I really need radiation.)
My radiation oncologist ordered an Axumin PET scan 2 weeks ago to be sure (as possible) that there is no metastatic cancer, and nothing showed up on the PET scan. He says now that they assume there are microscopic
cells in the prostatic bed and recommends radiation. Does anyone have any information about getting PSA testing
with blocking of heterophilic antibodies? Thank you for sharing any information that you might have.
prostatic bed and recommends rad

CORRECTION - I made a significant mistake in my first post. My post-prostatectomy PSA was 0.27 (not 2.7)! I must be really tired from sitting at the computer for a long time doing research into heterophilic antibodies!

Yes, the first post-prostatectomy PSA test (0.27) was done Oct. 27, 2019 at Vanderbilt, and the second PSA test
was done at my primary care doctor's office on Nov. 19, 2019. Second PSA was 0.3.

Vanderbilt did not put any information on the Portal regarding the test method that was used there. The PSA test
ordered by my primary care doctor was performed using the Siemens Chemiluminescent Method and was
performed by Quest Diagnostics.

Thank you very much, Sr Sailor, for your research and reply! I had actually seen the studies that you referenced,
and I emailed my surgeon's nurse practitioner (at Vanderbilt) about getting a PSA test that blocks heterophilic
antibodies. She emailed me back that my surgeon was not familiar with this issue and that the lab told her
they did not do such a test. I talked with my radiation oncologist about it, and he also was not familiar with this
issue but was very interested and ordered a mononucleosis test. My research indicates that the mononucleosis
test detects Epstein-Barr antibodies (but not other heterophilic antibodies). I've now found information on a
test at Quest diagnostics called the PSA Post-Prostatectomy with HAMA Treatment. This test blocks Human
Anti-Mouse Antibodies which are heterophilic antibodies and apparently can be a significant source of interference in a PSA test. (People can be exposed to mouse products during certain types of medical tests). I am going to request that test next week along with a test for Rheumatoid Factor.
Rheumatoid Factor is also a type of heterophilic antibody that can interfere with several medical assays, and although I tested negative for it several years
ago, I want to be tested for it again, especially since I have had autoimmune issues during the last five years.
I will report back on these test results. I certainly hope I can get them without having to go to several doctors; I don't mind paying out of pocket for them if I have to. I realize that the odds are that I will have
to have radiation, and I am willing to have it if I need it. I just want to be as sure as possible that I do really
need it since all my doctors say that my situation RE my good pathology report (clean margins, "organ confined") and relatively low Gleason score for my tumor (85% 3, 15% 4) with my persistent PSA is "very
unusual." Thank you again so much for taking time to research the information that you sent! I wish you
and all others on this site a good and joyful day. I'm really trying to take things "one day at a time" and to
enjoy all the blessings that each day brings. I wish that for all of you!

Thank you, Sr Sailor. Honestly, I was surprised that my Vanderbilt surgeon (at least according to the nurse practitioner who communicates for him) was not aware of the issue with the PSA test, because he is listed as
one of the authors on the Vanderbilt study. I know the study was done in 2008-2010 (published in 2011), and he probably wasn't involved in the actual compiling of information and writing of the paper. Also, that study concluded that no patient at Vanderbilt was overtreated as a result of undetected heterophilic antibodies. However, the last sentence of the paper (not the abstract) states, "When using PSA for post-prostatectomy
surveillance, it is crucial to confirm concerning values and always consider the presence of heterophilic antibodies if the PSA value does not correlate with the clinical scenario." I am seeing another RO at Vanderbilt
tomorrow and am seeing my family doctor next week. I hope that one of them will agree to do the Post-Prostatectomy PSA with HAMA treatment and the test for Rheumatoid Factor. As I said before, I realize I'll probably have to have radiation but just want to be diligent in ruling out the possibility of PSA test interference
so that I can feel good about going ahead with radiation. I'm thinking that because this is a rare phenomenon,
the "powers that be" don't consider it cost effective to test with the Scantibodies blocking tubes used in the
study and that this rare issue isn't considered statistically significant, but it is significant to me! I feel kind of
like my wife and I are on a desert island with our feet in quick sand trying to deal with this even though I am
being treated at a highly respected medical institution! Thank you for listening to all of this and for your good
wishes! I will report back regarding any further testing and my path forward.