questions @ Tdt and DNA/cytokeratin
Kathy Altig (Kathy_Altig@phsor.org)
Mon, 6 Oct 1997 14:17:53 -0700
My first question concerns Tdt by flow cytometry vs. Tdt by slide
(immunofluorescence). I ran flow cytometry on a Bone Marrow aspirate
from a patient previously diagnosed with RAEB. The clinician's
supposition was that he was converting to leukemia. The aspirate
contained a large group of cells that marked with CD33,CD34,MPO, (all
50%) and Tdt 50%. The Wright's stained slide confirmed the presence
of some very ugly cells in a high proportion. The pathologist writing
the interpretation wanted to check the Tdt (which didn't fit with her
probable interpretation) by slide. I performed the slide Tdt, and the
cells "appeared " to be positive in the cytoplasm, not the nuclear
areas. When I relayed this information, she felt that the flow Tdt
was not "real", and interpreted it as negative.
Does this mean that Tdt by flow (we use the Tago Fix & Perm kit) is
not a reliable test, and we must do the slide test? I must confess,
we hate doing the slide test; and the flow test has seemed to be a
great est -- however we have not done the test by both slide and flow
methodologies many times. We did a few times, in the beginning, then
after declaring the flow test good, we have done our best to avoid
doing the slide test.
What does it mean if the Tdt appears to be "cytoplasmically" positive
on the slide?
My second question has to do with cytokeratin staining with DNA
analysis. We have physicians requesting this for bladder washings,
paraffin prep.s and fresh frozen tumors. I am in the process of
collecting procedures and anecdotal information. Please send me
anything that would be helpful.
Thank you!
Kathy Altig
Providence Portland Medical Center
Kathy_Altig@ccmgate.phsor.org