Abstract: A single compartment, non-wedged shaped reagent cartridge for use in an automated clinical chemistry analyzer. The cartridge comprises a hollow relatively narrow reagent compartment formed by an axially elongated, bottom, an axially elongated top, a front end portion and a rear end portion extending vertically between the bottom and top and connecting to opposing right and left sidewalls for completing the reagent compartment. A shoulder engaging flange extends from the top for supporting the cartridge on a shoulder in a cartridge receiving carousel of an automated clinical analyzer including transfer probes for insertion into at least one opening in the top of the cartridge for fluid transfer into the clinical analyzer.