Posted 7/11/2017 7:36 PM (GMT 0)
Hey, Sam,
(1)
"it was actually quite startling to me to read of cases where there were cases of over treatment..."
Oh, yes. H**l, yes. Actually, tragic is a better word for it. Don't know if you've seen the Dr. Snuffy Myers short video "When recurrent PCa isn't cancer". He says he has seen a number of cases where uPSA becomes detectable, but stable, and notes that radiating benign tissue will always appear to be successful. (sigh).
(2)
On your questions about LabCorp test number and lower resolution:
Since my RALP in 04/2012, I have been getting LabCorp uPSA tests myself on a regular basis through the various online services that work with LabCorp. The current test number is 140731 and you can read about the details by googling "LabCorp ultrasensitive PSA". I believe 140731 has always been the test number, but don't quote me on that. I saved all my "results" printouts but not the "ordering" printouts over the years. The results printouts don't show the test number, but just "PSA, Ultrasensitive W/O Serial" and the test result, reference range, lab number, etc.
I have been working (and getting these tests' blood draws) in multiple cities over these years. The LabCorp test labs always seemed to be located in large cities, across the country from where i got the blood drawn. I guess LabCorp overnights the samples, since I quite often have my results by next day, even though the analysis was done far away from the blood draw.
Until 05/2013, my results showed as "< .006" and the test lab as "Kansas City, MO". On my 07/2013 test, the results showed as "< .015" and showed same over the years until my 2017 tests began showing low detectable results. The test lab on the result report changed to "Englewood, CO" for the 07/2013 test and was that for several years. Sometime in 2016, that changed to Dallas, TX and has been since. Every single one of these results reports has shown "Roche ECLIA methodology". I do not know the pattern or logic behind the changes in lower resolution and LabCorp test site city. I assumed all their major city labs used same type machines, resolution and methodology, but maybe that was my bad assumption.
(3)
Sorry, I did not catch, first time through, that you are just now trying to pin down your nadir uPSA, whereas my nadir was truly "undetectable" for years but is now rising. So I see your special concern, and I guess using multiple labs is a way to help you sort it out. In my case, I have been following the "same lab, same methodology" approach for five years and just praying it is good enough.
(4) I am copying (at bottom) portions of the "Limitations" and "Special Instructions" from the LabCorp 140731 test for benefit of other readers. They do not address the HAMA aspects you and I are concerned about, but rather more common confounding issues. But they do indicate some "flakiness" in these tests, and (to me) illustrate the problems with looking at .00x parts of billionths of ng/mL.
Robert
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The measured PSA value of a patient's sample can vary depending on the testing procedure used.2 PSA values determined on patient samples by different test procedures cannot be directly compared with one another and could be the cause of erroneous medical interpretations.2 Results cannot be interpreted as absolute evidence of the presence or absence of malignant disease.1 The PSA value should be used in conjunction with information from clinical evaluation and other diagnostic procedures.1
PSA levels can be elevated in patients with prostatitis.1 Treatment with antibiotics will decrease PSA by approximately 30% in men whose PSA elevation is due to prostatitis alone.1 PSA can also be increased in men with benign prostatic hyperplasia (BPH).1 PSA can be increased due to urethral or prostatic trauma.1 Prostate biopsy can cause substantial elevation of PSA levels.1 Cystoscopy may increase PSA levels immediately after testing.1 Ejaculation and DRE have been reported to increase PSA levels but studies have shown the effects to be variable or insignificant.1 PSA testing can be performed with reasonable accuracy after rectal examination.1
Surgical castration or medical castration (with LHRH-agonist or antiandrogen therapy) can lower PSA levels dramatically.1 Finasteride and dutasteride (5-α reductase inhibitors) can lower PSA levels by approximately 50% regardless of the dose.1 Prostatic intraepithelial neoplasia (PIN) does not increase PSA levels.1
PSA sampling should not be performed for at least six weeks after prostatic biopsy. This test is intended for use as an aid in the management of patients following surgical or medical treatment for prostate cancer.
Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy. This procedure does not provide serial monitoring; it is intended for one-time use only. If serial monitoring is required, please use the serial monitoring number 140723 to order.
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
Footnotes:
1. Prostate-Specific Antigen Best Practice Statement: 2009 Update, American Urologic Association. Available at:http://www.auanet.org/content/guideline-and-quality-care/clinical-guidelines/main-reports/psa09.pdf. Accessed March 3, 2011. PubMed 7880240
2. Total PSA, 2007-09, V EN Elescys 1010/2010 and Modular Analytics E170, Indi package insert, Indianapolis, IN: Roche Diagnostics. PubMed 10411025
References:
Mohler J, Bahnson RR, Boston B, et al. NCCN clinical practice guidelines in oncology: Prostate cancer. J Natl Compr Canc Netw. 2010; 8(2):162-200. PubMed 20141676