The present invention provides methods and kits for measuring a cell-mediated immune in a small volume of whole undiluted blood collected from a subject. The humidifier includes a water reservoir, an atomizer to atomize a supply of water, and an ultraviolet light source to expose the atomized water to germicidal light. The electrodes are configured to be in electrical contact with a contact electrode passing through a handle of the surgical tool. A head of the grinder contacts the floor surface and can follow contours of the floor surface.