A centrifuge having two arcuate slots to receive resilient, bendable mounting flanges that each carry a plurality of test tubes in side by side relation. The resilience of the mounting flanges enables them to flex and assume either the curvature of the slot, or a linear configuration enabling the flanges to be suspended in a flat condition, such as on a test rack. The arrays of test tubes is attached to the flanges via living hinges that enable the flexing to occur. The advantages are that simplified identification of individual test tubes, as well as reduced likelihood of intermixing of spillage are realized.