may–grünwald stain may–grünwald stain may–grünwald stain or may–grünwald–giemsa stain is used for the staining of slides obtained by fine-needle aspiration in a histopathology lab for the diagnosis of tumorous cells. may grünwald–giemsa staining of bone marrow cells taken from a patient with hereditary folate malabsorption, from a case report by yukari sakurai et al., 2022