Flow cytometry method can be helpful

Typical aggregometers use either optical measurements or impedance measurements -- and some offer both readings. Optical measurements are the 'classical' method, with a long history, but I think all optical measurements required PRP prep. A quick spin gets you PRP from whole blood, so I don't consider PRP prep a big hurdle to successful measurement. The Bio/Data PAP8 is an easy to use optical instrument. Impedance is a relatively newer measurement method, and despite the increasing availability of these instruments there may still controversy about whether the measurement is truly physiologically relevant (whereas optical measurement is more widely accepted). The advantage is that you can measure whole blood directly, so this might be an 'easier' measurement -- but again I do not see much problem in the quick centrifuge step to get PRP for optical measurements. Multiplate is an example of an impedance instrument. Chronolog offers instruments that can do both measurements. There are other instrument manufacturers for optical and impedance also -- these are ones that I have used at different times on previous research projects.

In my experience, both optical and impedance measurements are valid (although if you look hard enough you can find some differences). Either measurement is relatively easy, once you know how to run the instrument. Except for the quick PRP spin step, both measurements take about the same amount of time overall. An important consideration is the cost to operate: impedance measurements use special wires dipped into the samples; sometimes these are in single-use 'cups' or I think some are 'washable' wires that can be re-used (but I'm not sure how many times they can be re-used). Because of these wires, impedance will tend to cost more to run than optical systems. The optical systems do require specific cuvettes, but these are comparatively cheaper. In all cases you need to add an agonist, which most of the companies sell as reagents, and so you should consider cost of these also.

Thanks dear for detailed answer