Patent ID: 6977032

Claim:
A biosensor comprising an insulating base plate, an electrode system including a measuring electrode and a counter electrode provided on said base plate, a cover for covering said insulating base plate, at least one reaction layer containing oxidoreductase and/or an electron mediator, a sample solution supply pathway including said electrode system and said reaction layer and communicating with an air aperture at a terminal end side, a sample solution supply part and a filter provided between said sample solution supply pathway and said sample solution supply part to filter hemocytes, said biosensor being capable of sucking plasma with hemocytes therein filtered with said filter into said sample solution supply pathway due to capillarity, characterized in that a top face facing away from the base plate and an end face of a primary side portion of the filter are exposed to the outside and the sample solution supply part is formed adjacently to said primary side portion and defines a space located over said base plate, a rail is provided from said sample solution supply part to said filter so that said sample solution is concentrated at the top face and the end face of said filter.