Roche Assay vs. Siemens and Others

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jimlap
New Member


Date Joined Jan 2011
Total Posts : 2
   Posted 1/8/2011 9:52 PM (GMT -6)   
Has anyone noticed lately that the Roche ECLIA ultra-sensitive may yield results of <.01 (whch is a good thing) vs. .03 or so with other labs?  Which do you trust?
 
Jim

medved
Veteran Member


Date Joined Nov 2009
Total Posts : 1100
   Posted 1/8/2011 10:17 PM (GMT -6)   
I did extensive reading on the differences among assays a year or so ago. I will see if I can dig up the best of the articles, if you are interested. The bottom line is: one assay is not "better" or "more trustworthy" than the other, but the differences among them can be material -- particularly between those calibrated to the Hybritech standard and those calibrated to the WHO standard. (But it gets more complicated than that because some WHO-calibrated tests appear to perform more like Hybritech calibrated assays). In my opinion (and you should probably take my opinion with a grain of salt because I am not a doctor and am not educated in the sciences), this is one of the most important commonly overlooked issues in psa testing. The key, in my view, is to pick one lab and one assay and STICK WITH IT for all of your psa tests. Otherwise, you may think your psa is going up -- or down -- when it reality you are just being fooled by the lack of standardization among different assays.

Here is one article. It is not the best, but just one I could find quickly that provides some more detail:

http://www.cli-online.com/fileadmin/artimg/the-need-for-a-lower-total-psa-cut-off-value-with-psa-assays-calibrated-to-the-new-who-standard.pdf
Age 46.  Father died of p ca. 
My psa starting age 40: 1.4, 1.3, 1.43, 1.74, 1.7, 1.5, 1.5
 

jimlap
New Member


Date Joined Jan 2011
Total Posts : 2
   Posted 1/8/2011 10:33 PM (GMT -6)   
Thanks for the info.  I had Rrp in 2002.  My PSA's since then all had been <.003 to .005 (probably some noise). These were done on the Siemens 3rd generation I believe, and I did these in a city where I do not live.  I did these every six months.  I also did a PSA at Tricore every three months where I live.  Tricore was always <.01 until this Oct. when it came back as .03.  Obviously concerned, I called the tech and he told me they changed re-agents and kits in September.  I'm just frustrated there seems to be no standard and am wondering if the change in kits has something to do with it.  I also had two PSA's done at Labcorp for comparison a month apart and they came back as <.01.  I suppose I would like to believe the Labcorp results but Tricore is somewhat concerning.  Jim

Purgatory
Elite Member


Date Joined Oct 2008
Total Posts : 25393
   Posted 1/8/2011 10:36 PM (GMT -6)   
medved,

i agree with you findings. with one exception only, i have used the same lab for all my pSA tests since 2002. i like the consistency in doing it that way.

david
Age: 58, 56 dx, PSA: 7/07 5.8, 10/08 16.3
3rd Biopsy: 9/08 7 of 7 Positive, 40-90%, Gleason 4+3
open RP: 11/08, on catheters for 101 days
Path Rpt: Gleason 3+4, pT2c, 42g, 20% cancer, 1 pos marg
Incont & ED: None
Post Surgery PSA: 2/09 .05,5/09 .1, 6/09 .11. 8/09 .16
Post SRT PSA: 1/10 .12, 4/8 .04, 8/6 .06 11/10 Not taking it
Latest: 6 Corr Surgeries to Bladder Neck, SP Catheter since 10/1/9, SRT 39 Sess/72 gy ended 11/09, 21 Catheters, Ileal Conduit Surgery 9/23/10

An38
Veteran Member


Date Joined Mar 2010
Total Posts : 1152
   Posted 1/10/2011 7:52 AM (GMT -6)   
We use 2 labs now and they use different assays. The tests are done with my husband going at 7am to one collection centre and then at 7:30 to the next on the same day.

Both are ultrasensitive tests - Lab 1 (Prince Alfred) uses the Immulite 2000 3rd gen whereas Lab 2 (Douglas Hanly Moir) uses Abbott Architect. Both tests are I believe calibrated to the WHO standard. However as you can see that these two tests are giving us consistantly different results and I am trying to work out what's happening.

The UK government did a comparision of PSA assays in order to make good purchasing decisions in Feb 2010 and the results were published at this website.

http://www.immqas.org.uk/documents/TotalPSAAssays-EvaluationReport2010.pdf

When they compared the tests at a known reference PSA of 1.5 (see page 9) the Abbott Architect read it as slightly under 1.5 whereas the Immulite 2nd generation read it at 2 (!) and the Immulite 3rd generation read it at 1.7. This is a much wider distribution than I expected, if they have difficultly lining up at 1.5 then I am not surprised that they have difficulty lining up when the numbers are so much smaller and presumably more difficult. They have tested quite a few different assays here so I though it would be useful to post this.

We of course hope that the Abbott one is right as it is more favourable to us (see signature below). However we understand that the trend is the most important thing so we will continue to test at both laboratories two-monthly till the end of the first year after RP.

Regards,
An
Husband's age: 52. Sydney Australia.
Family history: Mat. grandfather died of PC at 72. Mat. uncle died of PC at 60. He has hereditary PC.
PSA: Aug07 - 2.5|Feb08 - 1.7|Oct09 - 3.67 (free PSA 27%)|Feb10 - 4.03 (free PSA 31%) |Jun10 - 2.69. DRE normal.
Biopsy 28Apr10: negative for a diagnosis of PC however 3 focal ASAPs “atypical, suspicious but not diagnostic” for PC. Review of biopsy by experienced pathologist, 1/12 core: 10% 3+3 (left transitional), 1/12 core: ASAP (left apex)
Nerve sparing RP, 20Aug10 with Dr Stricker. Post-op path: 3+4 (ISUP 2005). Neg (margins, seminal vesicles, extraprostatic extension). Multifocal, with main involvement in the fibro-muscular zone. T2C.
Post RP PSA,
Lab 1: Sep10 – 0.02|Nov10 – 0.03|Dec10 – 0.03
Lab 2: Nov 10 - 0.01|Dec10 – 0.01

Post Edited (An38) : 1/10/2011 2:40:15 PM (GMT-7)

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