A test sample container assembly for loading a plurality of test samples onto a test sample carousel of an automated analytical system and an automated, continuous and random access analytical system containing such test sample container assembly and capable of simultaneously effecting multiple assays of a plurality of liquid samples are disclosed. The test sample container assembly comprises (i) a housing with two parallel curved sides, said sides having the same radius of curvature as the test sample carousel, (ii) a top shelf with at least two openings for receiving test sample containers, (iii) a bottom parallel to and spaced apart from the top shelf defining with the curved surfaces therebetween a cavity, and (iv) wherein said bottom portion and said curved surfaces define a cavity therebetween wherein the at least two openings provide a predefined vertical alignment and the test sample container openings are presented in a plane parallel with the plane of the assembly shelf.