I'm not a biochemist, and it's been too long ago when I worked there to comment on what the current state of the art is in this area. What I recall is that at

I'm not a biochemist, and it's been too long ago when I worked there to comment on what the current state of the art is in this area. What I recall is that at the microfluidic level, a lot of the work becomes a mechanical issue not a biochemical one. You're working with very small samples in a disposable system (obviously cleaning a capillary between samples is practically impossible). Blood isn't the easiest substance to work with, especially when trying to move it through small channels. On top of that, now you're trying to detect very small amounts of antigen in an even tinier sample size. Your technology needs to be incredibly sensitive but have a decent resolution as well. Some antigens you want a simple positive/negative outcome. But with some other tests you want a level or range (like thyroid).