An automated system for testing liquid samples, comprising: a first analytical unit for carrying out at least one first diagnostic test comprising a rotatable first vessel holder provided with a plurality of reaction vessel seats for detachably holding reaction vessels; a second analytical unit for carrying out at least one second diagnostic test comprising a stationary linear second vessel holder provided with a plurality of reaction vessel seats for detachably holding reaction vessels; and a reaction vessel transferring device, the transferring device comprising at least one gripper for gripping one reaction vessel and being capable of transferring reaction vessels from the first vessel holder to the second vessel holder and/or from the second vessel holder to the first vessel holder; and characterized by further comprising a curved guiding groove, and further characterized in that the reaction vessel transferring device is translatable parallel to the second vessel holder and wherein the gripper is movable at least in part along a curved path between a picking position and at least one reaction vessel seat of the second vessel holder, the reaction vessel transferring device further comprising a linearly translatable socket which is guided by a linear guiding rail; a build-up, rotatably attached to the socket and having a guiding element which can be brought in engagement with the curved guiding groove and is configured to move along and being guided by the curved guiding groove to control rotation of the build-up with respect to the socket when linearly translating the socket with respect to the linear guiding rail, wherein the reaction vessel transferring device comprising a resilient device for pre-tensioning the build-up in rotation against the socket, and wherein the gripper is attached to the build-up. a first analytical unit for carrying out at least one first diagnostic test comprising a rotatable first vessel holder provided with a plurality of reaction vessel seats for detachably holding reaction vessels; a second analytical unit for carrying out at least one second diagnostic test comprising a stationary linear second vessel holder provided with a plurality of reaction vessel seats for detachably holding reaction vessels; and a reaction vessel transferring device, the transferring device comprising at least one gripper for gripping one reaction vessel and being capable of transferring reaction vessels from the first vessel holder to the second vessel holder and/or from the second vessel holder to the first vessel holder; and characterized by further comprising a curved guiding groove, and further characterized in that the reaction vessel transferring device is translatable parallel to the second vessel holder and wherein the gripper is movable at least in part along a curved path between a picking position and at least one reaction vessel seat of the second vessel holder, the reaction vessel transferring device further comprising a linearly translatable socket which is guided by a linear guiding rail; a build-up, rotatably attached to the socket and having a guiding element which can be brought in engagement with the curved guiding groove and is configured to move along and being guided by the curved guiding groove to control rotation of the build-up with respect to the socket when linearly translating the socket with respect to the linear guiding rail, wherein the reaction vessel transferring device comprising a resilient device for pre-tensioning the build-up in rotation against the socket, and wherein the gripper is attached to the build-up.