>From the dim reaches of my old med tech background, when you spin down
blood, collected with an anticoagulant, the red blood cell settle to the
bottom of tube, there is a fluffy white layer just above the RBC's, and
this is the buffy coat or white blood cells, which can then be removed
by pipetting or however it is done today.  One can take an aliquot of these 
cells and analyze their morhpology, count, etc. and even smear them on
a slide without RBC contamination.   Boy, it has been a long time since I
had to think about this, hope I was not off base.

Gayle Callis