Studies have shown that whiteboards support much cooperative work by for example strengthening awareness, improving communication, and reducing mental workload. In line with these predominantly positive findings, an emer-gency department (ED) turned to its whiteboard to improve the coordination of its work with blood tests. We investigate this use of the whiteboard through observations and in-formal interviews in the ED and analyze the ability of the whiteboard to support coordination and awareness in the work with blood tests. Our findings show limitations in the ability of the whiteboard to support awareness in a setting where the users are (locally) mobile, specifically in regard to information that requires continuous monitoring. We do however also find that the whiteboard safeguarded the work with blood tests against some risks by making blood-test information socially visible