which is the better method of slide preparation of a body fluid... direct from the fluid (like a thick film is made?) or from the deposit after centrifugation?

That is a choice left to the tech performing the work. If the cell density is high, it makes sense to look at the fluid as collected. If the cell count is low, you will be counting all day unless centrifugation is used.

I get a feeling that cells seem to shrink when slide is made by direct method. Is this really the case?

I discussed your observation with the Heme senior tech. Neither of us have experienced the effect you mention. The possibility of smudging cells when making a direct slide does exist, so obviously care should be taken when making a slide. Just the experience from here :-)

I always make the slide for differential using the cytospin. If the WCB content is elevated then a diluted aliquot (with saline) is used. The shrinking effect that you have metioned when making a push smear has to do with the concentration of cells and the viscosity of the body fluid. If the fluid is of low viscosity and elevated cell concentration you may see normal sized cells on a push smear but increase the viscosity with the same cell concentration and the cells will appear smaller. The cytospin has the advantage of using centrifugal force to push the cells onto the slide as opposed to speading them as is the case of the smear. Also, and perhaps most important, is that when making a cytospin use a drop or two of albumen (22%) prior to adding your specimen and this will allow for a slower and steady migration of the cells to the slide during centrifugation. The use of albumen is a good practice with low viscosity (thin) body fluids. The higher viscosity fluids like Synovial does not require albumen for a neat low cell concentration specimen. However, when employing hyaluronidase along with saline for dilution the initial viscosity of the neat specimen may be lowered enough where use of albumen may be necessary. It's late at night and I hope that I am making sense and I hope this helps.

Edited April 2, 201114 yr by rravkin@aol.com

I do exactly as rravkin and have had very good, consistant results.

dear rravkin, it sure has made sense.

Thanks a lot

It seems to me like there is much more of a tendency for distortion of the cells when a cytospin is used. I try to avoid it here, other techs use the cytospin almost exclusively, even to the extent that they will dilute a very thick specimen with saline before spinning so they can use the cytospin.

If a specimen is cloudy enough, after aliquoting to an EDTA, I will spin it and make a push-smear from the button. These slides stain with cells that look like a peripheral smear and I think that the differential distribution is maybe more accurate than what you would get from a cytospin. If the button is very small, you can always resuspend it and then go to the cytospin.

I agree that for very thin specimens like CSF that have to be cytospun, adding a drop of albumin to slow the cells down during spinning is important--otherwise some cells just get sucked into the filter paper. Beware of messed up diff %s if this occurs, some types cells will do this more than others.

Edited April 22, 201114 yr by SMILLER

The cyto spin is not an even distrubution due to centrifigal effects. The larger cells are heavier, etc. I find if you spin slower and longer, these can be minimized. Too much albumin makes the lymphs look "blasty". Don't use too much just enough to help preserve morphology and act as a glue to help cells adhere to the slide.