Abstract: A test module or reagent handling device for use with a clinical analyzer for conducting body serum assays and/or immunoassays; the test module coacting with the analyzer to selectively provide a plurality of liquid dilution and reagent materials to a serum sample, the test module having programmable valve means coacting with a dispense probe to serially: select a serum sample and to deposit said sample and liquid dilution material into a dilution cup or vessel; subsequentially withdraw a portion of the diluted serum from the dilution cup and to dispense said diluted serum portion along with at least one liquid reagent material into a reaction cup or vessel.

Abstract: In a fluid metering system, a plunger actuated syringe is coupled to at least one source of fluid, and a highly accurate friction drive is coupled to the plunger for moving fluid to a delivery outlet. The friction drive has a rack having a flat side and a rotatable circular drive shaft, or pinion, pressed against the flat side of the rack for moving the same by friction. Opposed guide rollers engage the rack in opposition to the flat side in straddling relation with the pinion for urging the rack thereagainst. A moveable swing arm supports one of the guide rollers against the rack. A spring leverages the swing arm and guide roller against the rack and transmits the force to the pinion. A positioning rod is provided for securing the swing arm and the moveable guide roller in a plane perpendicular to the flat side of the rack to prevent lateral motion of the rack and pinion whereby inaccuracies in the system may be minimized.