A blood analyzer comprising: a specimen preparation section for preparing a measurement specimen that is used to measure a white blood cell count among CBC measurement items; a measurement section for obtaining optical information from blood cells contained in the measurement specimen; and a controller carrying out operations comprising: classifying blood cells contained in the measurement specimen into at least white blood cells and blood cells suspected to be abnormal blood cells based on the optical information; obtaining distribution data of the white blood cells and distribution data of the blood cells suspected to be abnormal blood cells; counting the white blood cells based on the distribution data of the white blood cells; and determining presence or absence of the abnormal blood cells in the blood sample, based on the distribution data of the blood cells suspected to be abnormal blood cells. A blood analyzing method and a computer program product are also disclosed.