A lab rack rotator includes a motor coupled to a shaft arranged to rotate in at least one direction in response to the motor. One or more mounts are located along the surface of the shaft and are configured to receive a lab sample rack which holds a plurality of lab samples contained in lab sample containers such as test tubes. Rotation of the shaft permits inversion of the plurality of lab samples, for instance whole blood samples. The lab rack rotator increases the number of lab samples that may be agitated in an automated process while decreasing the amount of time required for necessary pre-testing agitation of samples.