This was in the late 80’s. I worked in Haematology in a pathology laboratory. We ran blood through analysers for testing. At that time it was the practice for blood from known positive HIV patients to have a warning label. The practice has now ceased in favour of “universal precautions”. Seeing the warning label was scary because you knew for sure that the tube you were opening (I needed to make blood smears for the microscope)contained HIV. It was just a psychological thing because you should always be careful but knowing for sure really made you think about it.

– Gail