Sometimes I think I'm too hard on myself. It takes years and years of practice to do a white cell differential confidently and accurately. I've been doing it for about a week and I can't seem to get it right. Those times when I'm not thinking that I'm too hard on myself, I think I'm just plain dumb. Here's what I have to do at work. The following four cells are completely different:

(Mouseover to see what they are.)
Sure, there are differences in these photos, anyone can pick that out. But these ones here are taken from different slides so the base coloration varies. And of course, not every cell is picture perfect: all of the cells--even cells of the same type--are not the same shape or size or colour. The myelocyte (4th cell) is a more mature version of the progranulocyte (3rd cell). These two cells are supposed to be more simlar to each other in appearance than any of the rest are. Keeping that in mind, that's just how much variation there is within cell types. I'm sitting at a scope trying to tell just why they're different and all the people beside me can do to help is say, "Of course they're different." I wish all the cells just came with labels--labels written in English. Hematology would be so much easier.

Photographs © Carden Jennings Publishing Co., Ltd, 2003.