RE: Reporting clinical results

Hi there Lydene,
Our lab reports findings based on CD45 gating. In cases of erythroid or megakaryocytic anomalies, we report the percentage of CD45 dim cells, with their corresponding phenotype.  Your reported percentage of blasts sounds reasonable for a finding consistent with the diagnosis of erythroleukemia. (for confirmation: Are the blasts CD117 or CD34/Glyc A positive?) 
The academic question is why? the difference in percentages. 
Your logic is reasonable regarding the discrepancies for differing blast percentages of flow versus smear morphology. Any type of centrifugation, and/or washing and lysing are sure to take a toll on a cell suspension. 
 
 We have found differences similar to this in a few cases of marrow aspirates from myeloma patients. The smear will show 80% myeloma cells but flow will confirm only 30% CD38bright/CD117/CD56 positive cells.
 
Cheers to you all, (and I hope, warm weather)
 
Ernest Stapleton 
Division Manager 
Immunology and Genetics Laboratories 
Room 1524 Health Sciences Center 
St. John's, Newfoundland 
A1B 3V6 Canada 
709-777-8654 

-----Original Message-----
From: Lydene McArthur [mailto:Lydene.McArthur@cdhb.govt.nz]
Sent: Thursday, December 14, 2006 10:59 PM
To: cyto-inbox
Subject: Reporting clinical results


Hi everyone
 
I would like to get some feedback about reporting clinical flow cytometry results for bone marrow samples.  Does everyone report the percentage of abnormal and normal cell populations present.  If so, what value do you use to express the result - do you report each population as a percentage of CD45 positive cells, or as a percentage of total nucleated cells in the sample.
 
My reason for asking - we have a bone marrow sample from a patient with erythroleukaemia.  The morphology differential shows 89% erythroid precursors and 4% blasts.  The flow cytometry results show 20% erythroblasts (bright CD71/glycophorin A) and a smaller number of myeloblasts.  The percentage of erythroblasts between the two techniques is markedly different.	I have tried to explain to our Haematologist this is most likely due to the red cell lysing technique used to prepare the sample which can result in selective loss of red cell precursors (we are using ammonium chloride).  But I don't know whether he believes me!!   
 
Does anyone else have experience with flow cytometry analysis of erythroleukaemia?.  How do you report the results when the erythroid cell percentages are so different between the two techniques.  
 
Many thanks and christmas cheers (hic!)
 
Lydene McArthur
 
Haematology Surface Markers
Canterbury Health Laboratories
Christchurch
New Zealand
Phone +64 3 3640 917
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