Microchip and method of using the same

1. A microchip including fluid circuits therein, the microchip comprising a first transparent substrate and a second substrate joined to the first transparent substrate, said second substrate having grooves provided at a substrate surface and said fluid circuits being defined by a substrate surface of said first transparent substrate facing said second substrate and said grooves,

wherein said fluid circuits comprise:

a first liquid reagent receptacle unit to store a first liquid reagent,

a first liquid reagent quantification unit connected to said first liquid reagent receptacle unit, wherein the first liquid reagent quantification unit quantifies said first liquid reagent,

a first overflow reagent storage unit connected to said first liquid reagent quantification unit, wherein the first overflow reagent storage unit stores said first liquid reagent overflowing from said first liquid reagent quantification unit and has a site irradiated with light to detect absence or presence of said first liquid reagent,

a specimen quantification unit that guantifies a specimen, said specimen quantification unit being a distinct unit from said first liquid regent quantification unit,

an overflow specimen storage unit connected to said specimen quantification unit, wherein the overflow specimen storage unit stores said specimen overflowing from said specimen quantification unit and has a site irradiated with light to detect absence or presence of said specimen, and

a first mixing unit connected to said first liquid reagent quantification unit and said specimen quantification unit, wherein the first mixing unit generates a first mixture by mixing a quantified specimen with a quantified first liquid reagent, said first mixing unit being a distinct unit from said first liquid reagent quantification unit and said specimen quantification unit.

2. The microchip according to claim 1 , further comprising:

a second liquid reagent receptacle unit arranged to store a second liquid reagent,

a second liquid reagent quantification unit connected to said second liquid reagent receptacle unit and arranged to quantify said second liquid reagent,

a second mixing unit connected to said first mixing unit and arranged to generate a second mixture by mixing said first mixture with said second liquid reagent, and

a detection unit connected to said second mixing unit and arranged to analyze said second mixture by optical measurement.

3. The microchip according to claim 1 , wherein said first transparent substrate has a through hole and has a specimen inlet which is connected to said specimen quantification unit via said through hole.

4. The microchip according to claim 1 , including a plurality of overflow liquid storage units, wherein said plurality of overflow liquid storage units are disposed on a circumference of the same circle at a surface of said second substrate.

5. The microchip according to claim 1 , including two layers of fluid circuits therein, formed by uniting together a first substrate that is a transparent substrate, a second substrate having groves provided at both surfaces of the substrate and through holes penetrating in the thickness direction, and a third substrate.

6. The microchip according to claim 5 , including a plurality of overflow liquid storage units, wherein one of said two layers of fluid circuits, located at a side of said first substrate, includes all the overflow liquid storage units.

7. The microchip according to claim 1 , wherein said second substrate is an opaque substrate.

8. The microchip according to claim 7 , wherein said second substrate is a black substrate.