Dear Stefanie, The number of cells necessary to get a decent result depends on the clinical question and the cell viability. When processing clinical specimens, we are often limited by the amount of material, especially with fine needle aspirates or cerebrospinal fluid. If flow cytometry is needed to answer a clinical question (e.g., reactive lymphocytes vs. small cell lymphocytic lymphoma), then I believe that it is better to aim for a qualitative, clinically important, answer than to reject a specimen for lack of statistical precision. I do not set a minimum threshold. If we receive a tiny specimen, we look at the clinical question, determine what is the minimum number of antibody tubes needed to provide an answer, centrifuge and wash the cells, and resuspend them in the minimum volume needed for those tubes (e.g., for 3 tubes, 9 antibodies @ 50 mcl cells/tube, we would resuspend in 200 mcl fluid). Analysis of as few as 100 lymphocytes can sometimes provide a definitive answer, such as distinguishing between a reactive T cell process and a monoclonal B cell population. Another approach is a two step approach. Stain one small aliquot of cells with CD45, CD5, and CD20. Analyze. You can quickly determine whether there are enough healthy cells to pursue further testing. And the good thing is, you don't have to worry about antigen excess! Irene Hello everybody! > >I am writing for the first time and would be interested in your experience >about how few cells are necessary to get decent results. Our lowest number >right now is 5000 per tube. Is there anyone who tries lower numbers? > >Many thanks for your help >Stefanie Reuss >MZ Nervenheilkunde - Neurologische Klinik mit Poliklinik >Rudolf-Bultmann-Str.8, 35039 Marburg, Germany, >Fax +49 6421 28 7055, Phone +49 6421 28 5480 > > Irene J.Check, Ph.D. Director, Clinical Laboratories Evanston Northwestern Healthcare 2650 Ridge Ave. Evanston IL 60201 847-570-2739 (voice) 847-570-1938 (fax) 847-570-2311 or 2312, pager 2885 (page)
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