Please Subscribe to get a daily link to Pat's blog via email


Your privacy is important to us. We will never spam you and keep your personal data secure.

FLC assays: sensistive test works well for some, not others

Home/About Pat, Diagnostics, Tips/FLC assays: sensistive test works well for some, not others

FLC assays: sensistive test works well for some, not others

It’s wonderful to have so many dear online friends looking out for you.  When suzierose commented–and then emailed me–suggesting that a FLC assay would be a more sensitive and accurate way to measure the progress that pomalidomide was or wasn’t makingm  I responded that I wasn’t familiar with that test.  Coincidentally, that’s one of the test results Danny Parker and his doctors use to monitor his myeloma levels, too.

Danny then followed up with a column about it:

More about alternative ways to monitor myeloma


Alarm bells should have been going off in my head.  How could I be a patient at top rated Moffitt Cancer Center and Mayo Clinic and not had this test done?

I’ve been so busy lately I didn’t take the time to check my own test results before responding. For me, checking certain lab numbers becomes a habit.  I often remind readers to pay attention to trends up or down.  That means monitoring the same numbers month to month.  So I follow a few key values and skim over the rest.   I learned that my doctors have been following my FLC assay ratio  for years!  FLC is an acronym for free light chains.   Moffitt’s reports doesn’t use the acronym.  Mayo Clinic does.

In a post I wrote earlier in the month, myeloma survivor and activist, Jack Aiello, called me on some inaccurate (sloppy) writing I’d done, referring to my free light chain ratio as “zero.”   Of course a ratio can never be zero.  It should have read, “one.”  What I meant to convey was that no myeloma activity was present in that test.

Blame it on chemo brain, being crazy busy with our move across the State of Florida, my pain or pain meds.  Why I failed to make the connection between my exchange with Jack, suzierose’s suggestion and Danny’s concern over his report showing a rising FLC ratio is beyond me.

Come to think about it, I’m not the only one who’s cognitively challenged here!  How many times have I written that the only reliable number my doctors have to work with is my M-spike?

Why haven’t my doctors suggested I pay more attention to My FLC ratio?  Because for me it’s  an unreliable measure.  Just as electopheresis testing of my urine always registers as normal.  I double checked.  My FLC assay ration runs in a narrow (normal) range between 1.0 and 1.7.  And it doesn’t necessarily rise when my M-spike does.  It was 1.17 when my M-spike was 0.2, 1.69 at 0.4 and  now that my spike is up to 0.7, the ratio is inexplicably down to 1.02.

Remember a while back when I wrote about trying to find a back door into several clinical trials that might have worked for me?  Each required an M-spike of at least 1.0, or an FLC ration of 10.  No go.  It’s the post I mentioned earlier that Jack commented about:

Clarification: How to qualify for a clinical trial


I spoke with Danny Parker by phone last evening.  It was great to hear his voice!  Danny wanted to remind me and our readers that often, the FLC assay isn’t necessary.  But in situations like his–where his doctors are trying to determine if his slumbering myeloma is awakening–or mine, where a more sensitive test might help determine if a new therapy is on track–FLC results can be a useful tool.  Just because it doesn’t work for me doesn’t mean it won’t work for you!

And from my standpoint, this is further evidence that Dr Alsina’s non-theory may hold some weight.  After all, it is strange that testing my urine shows nothing.  My IgG and IgA numbers are fine.  FLC ratio is OK.  My latest bone marrow biopsy (it was last year) showed no  myeloma cells.  And yet my bones are starting to look like Swiss cheese!

I’m proof that testing for–and monitoring–multiple myeloma still has a long way to go.

I do have a solution: stick me in the circus and let me entertain medical visitors with my amazing bones full of holes!  There’s an example of my long lost sardonic wit!

Feel good and keep smiling!  Pat