I will said that for some samples like CSF, is pretty normal to have very
low number of cells, actually is normal to find less than 10 cells/mm3.
However, to make diagnosis with low number of cells is a completely
different ball game. At that point is very important to have very well set
up your staining technique and your setting of the equipment should be very
well defined. Moreover, you can also should define that your procedures
are very reproducible and be sure that there is not chance that the
multicolor analysis has compensation problems (pretty often with three
colors). Then you can said that your results represent the real situation
of the CSF of your patient.
Recently there is a growing number of publications, mainly due to the
tetramers technology, that define as significant some numbers like 0.005%
for a sample of 200.000 cells (J of Imm and J Exp Med). That means about
100 cells having this marker. I found a little bit disturbing to jump from
this type of in vitro test to the bed of patients and believe that 100
cells for this type of assays is significant. Therefore, reporting that
100 cells in the CSF of a patient is also significant. I just remind to
some of the nonmedical community here, that to get a CSF sample without any
possibility of contaminating blood is a real feat and not too many profis
can boast of having a reproducible tap techniques without blood
contamination. You do not need too much, just enought in the walls of the
needle and your small population is obscure for the other cells coming from
the blood.
I hope that my comments will be helpful to you.
Regards Rafael
\|/
(o o)
________________________________oOo__(_)__oOo_________________________________
___/\_ | Rafael Nunez mailto:rafaeln@vetvir.unizh.ch
/ o \/| | University Inst.for Virology http://www.vetvir.unizh.ch/
/ _| | Winterthurerstr. 266a Telephone: (+41) 1 6358710
/_/\__/-\/ | 8057 Zurich SWITZERLAND Faximile : (+41) 1 6358911
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