Patent ID: 7144382

Claim:
A device for treating a fluid-like sample, in particular a body fluid such as blood, with treatment fluid, wherein the device comprises: a tubular container with a tube wall extending in the longitudinal direction from an upstream end of the tube to a downstream end of the tube; a first piston that is fitted in the tubular container and can be moved in the longitudinal direction thereof; a second piston that is fitted in the tubular container upstream of the first piston and can be moved in the longitudinal direction thereof; a piston gap that is located between the first and the second piston and is delimited by the first piston, the second piston and the section of the tube wall extending between them; a treatment fluid provided in the piston gap; an inlet port that is provided on the tube wall and has an inlet opening emerging into the tubular container, for feeding in the sample; an outlet port that is provided on the tube wall and has an outlet opening, downstream of the inlet opening, emerging into the tubular container, for discharging the sample treated with treatment fluid; a plunger that can be moved in the longitudinal direction of the tubular container; and coupling means which couple the first piston, the second piston, the plunger and the tubular container to one another in such a way that by moving the plunger in a single direction running parallel to the tubular container the first and the second piston move in the downstream direction from an initial position, via a first intermediate state and a second intermediate state, into an end position, the volume of the piston gap increasing between the initial position and the first intermediate state, remaining the same between the first and second intermediate state and decreasing between the second intermediate state and the end position; the inlet opening being located in a section of the tube wall that during the stage between the initial position and the first intermediate state, or at least during part of this stage, forms part of the boundary of the piston gap, and the outlet opening being located in a section of the tube wall that during the stage between the second intermediate state and the end position, or at least during part of this stage, forms part of the boundary of the piston gap wherein said device further comprises a capillary, wherein the capillary can be connected to the inlet port, and wherein the capillary contains an anticoagulant and the capillary can be inserted in the inlet port in a manner that produces a seal.