Abstract: Embodiments of a carrier and methods of its use are disclosed. In one method, a carrier is used with a container having a positioning device to be used with a medical diagnostic analyzer having a container loading device. This method comprises releasably mating a container retaining member disposed on the carrier with the positioning device on the container. The container retaining member on the carrier is substantially aligned with the container loading device on the medical diagnostic analyzer. The container is moved from the container retaining member on the carrier to the container loading device on the medical diagnostic analyzer.