The invention pertains to a tube rotator for rotating test tubes arranged in a tube rack, comprising a pivoted lever having two lever arms, a friction wheel, rotatably fixed to one lever arm and arranged to be brought in or out of contact with at least one test tube for rotating the test tube by friction, a first actuator, rotatably coupled to the friction wheel, a pretensioner, capable of generating a pretensioning force acting on the lever for pivoting the lever in one pivoting direction, an eccentric, rotatably fixed with respect to the base, arranged to roll off the other lever arm for pivoting the lever in the other pivoting direction, and a second actuator, rotatably coupled to the eccentric. It further pertains to a system and process for reading information of machine-readable labels of test tubes in which a tube rack is made to pass a reader, the tube rotator rotates at least one test tube and the reader is used to read information provided by the labels of the test tubes.