Abstract: A reagent segment including a body and trough formed therein with the floor of the trough sloped towards a drainage zone. The reagent segment is adapted for transporting reagents within an automated analyzer by having at least two protrusions on the exterior wall of the trough that fit within corresponding cavities of a transport arm. The reagent segment is retained by a latching mechanism through a protuberance on the exterior surface of the trough that conforms with a hole in the latching mechanism. The reagent segment can also have a concave depression on the interior surface of the trough at the drainage zone. The depression can coincide with the protuberance on the exterior surface of the trough that associates with the hole in the latching mechanism. Further, the reagent segment may include at least one indexing rib, between the exterior surface of the trough and the rim of the body, that can be inserted within an indexing slot of a holding means.