Yes, and I understand what you are saying. We don't have a large number of body fluid counts (about 1/day) and we seem to get them in batches, none for a few days, then 3-4 in one day, and not all of them are run through our analyzer (CSF, extremely low cell counts below linearity, so small a specimen volume, etc.) It doesn't seem cost effective to buy a commercial control when it is easy to look at the cytospin (which we would make on the specimen anyway) and confirm that the cell count appears to match. Besides, we very rarely see high enough RBC counts on body fluids that would compare to a peripheral blood cell count. If we do they are a usually clotted, so a cell count cannot be assessed, or b, if they are that high they are run on our Sysmex and the lower control level if adequate. What we do is a simple, cost effective procedural control that suits our test volume and type of specimen seen. If we saw a higher volume of specimens that had a significant cell counts, I would re-think our control method.