Blast % in marrow vs. blast % in flow cytometry

[LizR]

Why do blast counts differ from the marrow to flow cytometry? The numbers are always different and sometimes one is higher and sometimes the other.

[tytd]

Hi Liz,
I cannot really answer the question WHY, but there is often a discrepancy between the blast cell count in the marrow microscopic report and that on the flow cytometry report. What I do know is that I have heard several MDS experts on the AAMDS webinars or lectures say that the microscopic interpretation of the blast number on the bone marrow slide by the pathologist is better or more accurate than the flow cytometry reading and should be used when making prognostic determinations and making treatment decisions. If anyone out there knows why that is or if that is not true, please inform us. tytd

[revchris5802]

We expect to find some blasts in the bone marrow. That is where the blood cells are formed, so around 2% blasts should be there. What we don't expect is to find any in the peripheral blood. Blood cells are released into the blood stream after they mature. So we naturally see some difference. In any case, if there is a clone line present, that suggests a malignancy. In my case, I have 10% blasts in my bone marrow, but they are not malignant. It's very strange so I'm on watch and wait, even though my neutrophils are under 500, considered to be severe. My platelets hang out in the 70's and I'm mildly anemic with a slow descent downward. I can do a GCSF test if the marrow stays non cancerous. They would like to see a higher white blood cell count, but they also do not want to stimulate cancer by giving me the drug too early. In the meantime, I feel find.