Thursday, January 29, 2015

The things that make you go Ugh!


In November I had a CA-125 blood test. It came back 21.  The previous result was 14. I went for a retest in December and it came back 20. So it looks like it is now stable but at a different level. Keep in mind that my CA-125 was 17 when I recurred on my liver and spleen in 2008 so of course there is concern that my number was trending up - even in the normal range.

I decided to look more closely at the test results sheet because the results were reported as normal < 35 and I had thought the normal for the tests I had been having was < 21. 

Here is what I found on the sheet: 
" THIS TEST WAS PERFORMED USING THE BECKMAN COULTER CHEMILUMINESCENT METHOD. VALUES OBTAINED FROM DIFFERENT ASSAY METHODS CANNOT BE USED INTERCHANGEABLY. CA125 LEVELS, REGARDLESS OF VALUE, SHOULD NOT BE INTERPRETED AS ABSOLUTE EVIDENCE OF THE PRESENCE OR ABSENCE OF DISEASE.
"

So I went back to the report from August 2014 and sure enough the  normal for the test was reported < 21. 

The report said:

" THIS TEST WAS PERFORMED USING THE SIEMENS (DPC) CHEMILUMINESCENT METHOD. VALUES OBTAINED FROM DIFFERENT ASSAY METHODS CANNOT BE USED INTERCHANGEABLY. CA 125 LEVELS, REGARDLESS OF VALUE, SHOULD NOT BE INTERPRETED AS ABSOLUTE EVIDENCE OF THE PRESENCE OR ABSENCE OF DISEASE."

Ugh!  "Look they went and changed the method!" Maybe that is why my CA-125 went up. The last time the method was changed the lab followed it using both tests for a few months to see how the results correlated.  I was in treatment then and we were following it closely to make sure the chemo was working.

Being the research "hound" that I am I got on Google and investigated how the tests are done and what the difference was between the two methods.

I learned that both tests -  are chemiluminescent immunoassay tests. They use a monoclonal anti-CA125 antigen alkaline phosphatase conjugate and paramagnetic particles which are then separated in a magnetic field. A chemiluminescent substrate is added and the light generated by the reaction is measured with a luminometer. The light produced is proportional to the concentration of CA-125 antigen. 

From what I read the Beckman test uses two mouse monoclonal antibodies while the Siemen uses one mouse antibody and one rabbit monoclonal antibody. I am going to assume that is was causes the difference in results since all the tests were being done by the same lab.

The up and down of CA-125 results causes enough anxiety without having a different  method which could be the cause of the change thrown into the mix. 

I probably should have looked more closely at the results when they first came in before getting nervous. 

I will be seeing my gyn onc in February and had a CT scan today so I think I will have my answer if it is something I should really worry about. 

Dee
Every Day is a Blessing!


 



4 comments:

Karen Herrmann said...

I can totally relate. As far as I know, I have always had the same test method, but in mid-2012, mine very slowly crept up...one point at a time for several tests then it jumped 4, then 10 and sure enough, I had recurred for the second time even though I was still in the "below 35" normal range, in fact at 28, I had two very visible on scan, nodules that were later removed. I am now back to being at 11. I am so grateful that my Dr trusts my results and that my CA-125 seems to be a very good indicator for me. It is now 5 years since my original diagnosis and I seem to be in remission again and I feel great - I just hope they get some of the seemingly effective treatments on the horizon approved before I recur again. I hope all is well with your tests.
Karen

Dee said...

Thanks for your comment Karen. I am so happy that you are once again in remission.Like you I like to follow what treatments are in the pipeline so I am prepared. though ope to never use that information though

Not Dead Yet said...

Hi!
I have stage 4 ovarian cancer, terminal.

I have THREE labs doing CA-125 tests. Phew! Jumping from one result to the next at different labs. 65, 210, 184, 85, all the advice says you can't compare apples to oranges. . .

I actually have decent medical care in Virginia, but am doing an out-of-state clinical trial right now and using a very local (rural) lab for most, but not all, of my bloodwork.
My doctors are gung-ho about not comparing CA-125 results between labs, but hubby and I can't resist it. So many different results, DO they mean something?

So a lab manager at my local non-hospital lab answered my call today. I told him that I needed to get a ballpark idea of the variance between different machines, and different methodologies, of analyzing CA-125 counts. I mean, if you went to one lab and got a count of 100, could you go to a different lab on the same day and get a count of 50? What variance is "normal"?

The lab manager gave a good answer. He said that CA-125 counts do still have variances, but the test has been around long enough to where it's getting much more "standard" results. He told me that besides differences in labs and methodologies, a count can be affected by hydration, dehydration, etc etc. so that the next day your CA-125 levels could vary just by whatever ELSE you body is doing.

I pressed him for a variance number. He called it at 20%. If your CA-125 is different by 20%, it could be lab, body condition, etc. But a change that is MORE than 20% probably reflects an actual true change. In the HIGHER levels.

For you people that are looking at really low CA-125 counts, don't get excited about the 20% thing (lab manager tried to make this VERY clear) Obviously, if your CA-125 count jumped from 10 to 15, that would be insignificant.

Some women are hitting CA-125 levels at 600 or 1600, which put my 210 to shame.
Personally, now, if I tested at 210, and dropped to 200, I would not particularly perceive that as a big change in my cancer, I would more likely wonder. . ."was it really hot that day?"

Dee said...

Thanks Not Dead Yet for your comment . I did not realize that hydration who affect a number. I did know the inflammation could cause the number to rise.
May your CA-125 stay low.
Dee