Patent ID: 8623280

Claim:
A device for measuring blood coagulation time, comprising: (a) a first substrate; (b) a second substrate; (c) a spacer layer disposed between the first and second substrates, said spacer layer having an opening formed therein defining a sample receiving chamber, a vented sink chamber, and an elongated reservoir forming a conduit for liquid movement between the sample receiving chamber and the sink chamber; (d) a first electrode disposed on the first substrate, said first electrode being exposed through the reservoir portion of the opening in the spacer layer; and (e) a second electrode disposed on the second substrate, said second electrode being exposed through the reservoir portion of the opening in the spacer layer; wherein the first and second electrodes are in electrically conductive contact with the elongated reservoir such that an electrical signal can be detected between the first and second electrodes when a conductive liquid sample is disposed in the reservoir and at least one of the electrodes is electrically insulated from the sample receiving chamber and from the sink chamber, wherein the relative sizes of the reservoir, the sink, and a region at the connection of the reservoir and the sink are such that the time required for emptying sample from the reservoir into the sink to occur in the absence of coagulation is greater than the time required for coagulation to occur; and (f) first and second contact leads extending from the first and second electrodes, respectively, for connection of the device to an apparatus for measuring an electrochemical signal between the first and second electrodes through a sample in the reservoir.