We were just sited for this at our recent JCAHO inspection. We were told that it is not acceptable to JCAHO to test just one open vial of the lot number that we have to check all open vials if they are being used. The inspector made reference to a CLIA regulation but I was not able to find one, however the JCAHO standard is very specific. We are not CAP accredited. Standard number: QC.5.220 states :"each opened vial of antisera, reactive cells, and reagents is tested for reactivity on each day of use and when a new lot of reagents is first used".