A mysterious malady: the Malachowski-Wright-Giemsa stain to the rescue.

A patient entered hospital with a puzzling absolute monocytosis. Admitting blood smears had been stained with Diff-Quik, a Romanowsky stain. When additional smears were stained using a standard Malachowski-Wright-Giemsa method, the reason for the monocytosis became abundantly clear.