Permanent preparations of granulocyte-macrophage cultures in agar gel.

A simple method for the permanent preservation of agar cultures is described. The technique involves fixation of agar cultures after incubation, drying, and subsequent remounting and staining on glass slides. The technique permits differential counting of colony type, approximate quantitation of cell numbers within individual colonies or clusters, and permanent preservation of cultures for purposes of interlaboratory standardization, and for routine reference in patient records.