A self-adjusting linkable carrier for sample tubes, cuvettes, cells and the like comprising a longitudinally symmetrical vertically oriented polygonal body having two pairs of orthogonally disposed opposed vertical faces and a horizontal bottom sliding surface is disclosed. The top surface of the body is provided with a central bore opening into a vertical cavity adapted to releasably receive and retain a wide variety of sample tube configurations in a stable vertical orientation. Machine readable indicia may be provided on the external surface and vertical slots are provided in each external face to provide access to the central vertical cavity. A releasably locking horizontally aligned dovetail feature is provided to link adjacent carriers into conveniently handled racks or magazines which may be assembled and disassembled by machine. Additional horizontally sliding indexing elements are provided to facilitate the stable storage and transport of the carrier.