The technology does not provide a
precise count of white blood cells, but reveals whether patients are above or below the threshold considered dangerous — defined as 500 neutrophils (the most common type of white blood cell) per
microliter of blood.
«When the capillary is filled, we have a very
precise volume of blood, about five
microliters, which is less than a droplet — much less than what is required by other anemia tests,» explained Erika Tyburski, the paper's first author and leader of the undergraduate team that developed the device.