A method for detecting foam in a specimen container , said method comprising: transporting a specimen container into a locator well of a container locator device ; rotating the container locator device to an imaging work station where the specimen container can be imaged; centering the specimen container in the locator well, wherein the centering comprises providing a fence adjacent to the specimen container at the imaging work station, wherein the fence is positioned such that it pushes the specimen container into alignment with a vertical center line of an axis of rotation if the specimen container moves out of alignment with said vertical center line of the axis of rotation, optionally wherein the fence is resilient such that if the specimen container pushes into the fence, the fence rebounds to push the specimen container back towards the center of the imaging work station; rotating the specimen container around a vertical axis in the locator well; imaging a series of overlapping images covering a circumference of the specimen container during the rotation, illuminating the specimen container with blue light from a light bar during imaging of the specimen container to enhance contrast between a fluid in the specimen container and a background of the locator well, wherein the light bar is positioned at an angle relative to the vertical axis to optimize illumination for the detection of foam; analyzing the series of overlapping images of the specimen container captured during the rotation; and detecting foam in the specimen container based on the analysis of the series of overlapping images; wherein said analyzing and detecting is carried out by use of a server comprising a processor and memory, the memory having computer readable program code, and the processor programmed for said imaging, analyzing and detecting. transporting a specimen container into a locator well of a container locator device ; rotating the container locator device to an imaging work station where the specimen container can be imaged; centering the specimen container in the locator well, wherein the centering comprises providing a fence adjacent to the specimen container at the imaging work station, wherein the fence is positioned such that it pushes the specimen container into alignment with a vertical center line of an axis of rotation if the specimen container moves out of alignment with said vertical center line of the axis of rotation, optionally wherein the fence is resilient such that if the specimen container pushes into the fence, the fence rebounds to push the specimen container back towards the center of the imaging work station; rotating the specimen container around a vertical axis in the locator well; imaging a series of overlapping images covering a circumference of the specimen container during the rotation, illuminating the specimen container with blue light from a light bar during imaging of the specimen container to enhance contrast between a fluid in the specimen container and a background of the locator well, wherein the light bar is positioned at an angle relative to the vertical axis to optimize illumination for the detection of foam; analyzing the series of overlapping images of the specimen container captured during the rotation; and detecting foam in the specimen container based on the analysis of the series of overlapping images; wherein said analyzing and detecting is carried out by use of a server comprising a processor and memory, the memory having computer readable program code, and the processor programmed for said imaging, analyzing and detecting. <EOS>