Hi --
We have been using ARUP since diagnosis and oddly enough our first (and second) PCRs were not useable (not ARUP's fault in either instance).
Here are a few things that I've learned over the years.
I was specifically told last year that ARUP's medical director did not believe in reporting log reductions as he felt it was misleading on an individual basis. In other words, his opinion was that a person's log reduction is most accurately calculated on the basis of their own starting PCR value (as you know, a lab baseline is the average starting PCR for all newly-diagnosed patients for that lab and it can vary dramatically from any given person's starting PCR - either higher or lower).
This philosophy, while commendable in terms of absolute accuracy, does pose a problem when you do not have a starting PCR from which to calculate your own log reduction.
However, one thing to keep in mind is that you can always get a rough idea of your "progress" by looking to see what the your log reduction has been between your own multiple samples over time.
Another thing to consider is that several experts have said that when a patient achieves CCR that typically correlates to a 1.5 to 2 log reduction by PCR (please note that this is a VERY rough rule of thumb -- and, admittedly, the two are measuring two entirely different things!). You don't say whether you've had a bone marrow biopsy/aspiration since diagnosis but that info would surely be helpful. If you're CCR in 10 months, excellent.
Anyway, let me sum it up with a real life example:
.009 -- and CCR by BMA (0 of 20) -- 6 months from diagnosis
.00089
.00144
.00025
.00034
.00035
.00010
.00004 -- almost 3 years from diagnosis
So the difference between .009 and .00004 is a 2.4 log reduction PLUS whatever reduction had already occurred by the time we had reached CCR. So 2.4 plus (conservatively) 1.5 and thus a total 3.9 log reduction or something in that ballpark. Our onc agrees.
Long story short, though, the real take-home message is that it's the trend that is the important thing. I remember how difficult it was to wait to see a trend develop. If we take just the two numbers you have, it would seem that you have declined within the last 5 months -- so you'd like to see that continue going forward.
One last word of caution -- never switch between labs -- that creates complete confusion in trying to compare results.
Good luck!
Stephanie
