5 replies to this topic

[Taylor]

I, like everyone else here, had to have a BMB at diagnosis to confirm the Ph+ chromosome.  But my onc told me on my first follow-up, which I later discovered here too when I first began posting, was that peripheral blood is now the norm for follow-up FISH and PCR testing since the tests are good enough to detect leukemia in the blood.

My question is: why is there a difference?  It would seem to me that if they needed to check the marrow to confirm at dx, they would need to check the marrow for overall progress.  I'm just curious to this as I will be getting a FISH and/or PCR done in August at my 6 month follow-up.

[Trey]

The test required for diagnosis is a Bone Marrow Biopsy (BMB) which examines the actual chromosome structure under a microscope.  During this test the Pathologist can actually see the translocated chromosomes.  While that BMB was being done (creating a hole in the hip bone), marrow fluid was also taken (Bone Marrow Aspirate -- BMA) and separate tests such as a FISH and/or PCR were done on that sample.  Unless you love getting punctured in the hip, the blood FISH and PCR are standard procedure after diagnosis, except that another BMB may be done in the fututre to check marrow status.

If you want more info on this subject you could read this:

http://community.lls.org/docs/DOC-1273

[sdl722]

Taylor,

I'd be happy to not have frequent BMB/BMAs.  I am on a research study and the protocol requires me to have a BMA every 3 months for the first year and then every 6 months for the second year.  I've got my 3 month check up at the end of the month, so I'm going to be getting poked a lot more times over the next year.

Stephen

[Happycat]

Trey,

They can't get a standard chromosome karyotype (the actual pics of chromosomes) from a blood sample?  I had one done years ago when I was doing infertility treatments, and I thought that was just a blood draw.  I know for darn sure they didn't poke any holes in my bones, would've remembered that!  Now that has me wondering if they used one of the eggs in the ovary for the test??  It was kinda cool getting to see a snapshot of your own chromosomes, although it was much cooler back in 1999 when they were all normal!

Traci   

[Trey]

A BMB-style cytogenetics test on a peripheral blood sample is impractical for disease diagnosis because circulating blood lacks sufficient concentration of WBC progenitor cells in the status of division.  They are concentrated in the marrow, but "rare" (a relative term) in the blood.  But if a person just wants to capture a view of one cell's chromosomes, it can be done (as in your case for fertility testing).  A CML FISH will provide a karyotype readout showing the presence of the Philadelphia Chromosome, but a FISH should not be the sole method of diagnosing CML (see NCCN Guidelines) since it cannot show everything a BMB can show, and also the FISH is like poking around in the dark unless the doc is very sure which type of disorder is supected (there are thousands of types of FISH tests -- how do you pick the CML one when you don't know the diagnosis, except to guess?).

Regarding whether they used an egg to do your 1999 cytogenetics, the egg only has 23 chromosomes (not the full 46).

[Happycat]

Trey,

Thanks for the explanation.  Since they showed me the chromosome pairs, it must have been from the blood sample and not an egg.  (Good thing, too, since the eggs are far more precious to the typical IF'er!)

Traci