Patent ID: 8318439
Filing Date: 2012-11-27
Classification: B01L,G01N

Abstract:
1. A microfluidic cartridge for performing a blood type assay or crossmatch, the microfluidic cartridge comprising: a) a body member comprising a substrate or substrates and having a reaction channel enclosed therein, said reaction channel having a first end and a second end; b) a first and a second intake channel fluidly joined to said first end of said reaction channel at a staging union; said first intake channel for conveying a first fluid and said second intake channel for conveying a second fluid; wherein said staging union comprises a dual capillary stop enabled to simultaneously release said first and second fluids into said reaction channel in response to a start signal, such that the fluids flow one on top of the other as contacting lamellae of a horizontally-stratified fluid diffusion interface; c) a downstream flow control channel fluidly joined to the second end of said reaction channel, wherein the downstream flow control channel comprises an elongate runoff channel segment configured to enable capillary force-driven flow therein, said runoff channel segment having reverse tapered walls, a volume, and a wettable internal surface, wherein said reverse tapered walls broaden in aspect ratio from upstream to downstream so that capillary force and viscous drag are balanced to sustain said fluid flow in said upstream reaction channel for the duration of wetout of the downstream runoff channel volume; d) a vent or check valve with vent downstream of or terminating said downstream flow control channel.