Patent ID: 7569373

Claim:
A method for counting megakaryocytes in a bone marrow sample which comprises: preparing a measurement sample by lysing erythrocytes in the bone marrow sample and staining nucleic acid in the megakaryocytes with a fluorescent dye; irradiating the measurement sample with light from an optical system; detecting forward scattered light, side scattered light and fluorescence which is emitted from cells in the irradiated measurement sample; and counting megakaryocytes in the irradiated measurement sample comprising: specifying first cells containing megakaryocytes from the cells in the irradiated measurement sample by detected forward scattered light, specifying second cells containing megakaryocytes from the cells in the same irradiated measurement sample as the first cells by detected side scattered light and by detected fluorescence; and counting megakaryocytes which belong commonly to both of the specified first cells and the specified second cells.