I am working on an external quality assessment where we make large quantities of different smears some of them requires fresh white blood cells. The procedures suggests the use of WBC from fresh human blood( taken the same day we start making and processing the smears)

The problem with this is that it is not sustainable or not consistent as blood donors aren't always available where I work. If we happen to have a donor it would hardly be a good timing as we need fresh blood for a good looking WBC.

Do you have any suggestions for a better procedures and/or a better and readily available source of WBC source of?