So my 3 month PCR was 6% on one test that my local Onc sent off (I think LabCorp) but my "specialist" Onc said he didn't really like that lab and used a different lab (tested three weeks after the first) and the result was 12.5%. I don't think it actually went up in this time (god, I hope not) but are variances in lab results that great?

3 mos PCR... different lab numbers
#1
Posted 03 April 2014 - 12:11 PM
January 15: .53%
April 15: .78%
July 15: 1.1% - upped dosage to 400mg after this test
Oct 15: .85%
December 15: .28%
March 16: .29%
July 16: .34%
October 16: .11%
January 17: .081%
April 17: .055%
July 17: .135%
Oct 17: .008%
#2
Posted 03 April 2014 - 08:10 PM
The simple answer to your question is yes. It's not just between labs but also to do with the test - you may even see that much difference with the same sample tested at the same lab. So don't take your "increase" personally... welcome to the world of PCR testing. They say we should only start worrying when we see a big jump (> a factor of 10 e.g. 6% to 60%) and even then the first thing they would do would be to run another PCR plus maybe some other tests if your numbers are high enough.
It is important to stick with the same lab as much as possible to remove at least once source of uncertainty, so your doc has done the right thing in re-testing with a lab he trusts early on.
Dx Dec 2010 @37
2x IVF egg collection
Glivec 600 & 800mg
PCRU March 2012
Unsuccessful pregnancy attempt - relapsed, 3 months interferon (intron A), bad side effects from interferon
Nilotinib 600mg Oct 2012
PCRU April 2013, 2 years MR4.5 mostly PCRU with a few blips
April 2015 stopped again for pregnancy attempt (donor egg), pregnant first transfer, 0.110 at 10wks, 2.1 at 14wks, 4.2 at 16wks, started interferon, slow dose increase to 25MIU per wk, at full dose PCR< 1 for remainder of pregnancy
Healthy baby girl Jan 2016, breastfed one month
Nilotinib 600mg Feb 2016
MMR May 2016
PCRU Feb 2017
#3
Posted 03 April 2014 - 08:30 PM
PCR is not very accurate above CCyR levels, which is about 1% Also, different labs use different equipment and chemical reagents. Further, different labs use different control genes for testing. And if those are not enough, different labs have different reporting standards (International vs internal). Oh yes, and lab personnel can also affect the outcome by using various testing procedures.
http://community.lls.org/docs/DOC-1273
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