[Visual classification of erythrocytes in blood smears from normal subjects and patients]

Erythrocytes on specially prepared and coloured blood smears can be classified not only by idcture analysis but also by phase contrast microscopy. Parameters of change for the peripheral zone area and pallor area (phase contrast value PW and index of erythrocyte changes Ev-I) serve as classificators of visual technique. 449 blood smears of the same number of male and female grown-up persons, whose diagnosis was unknown at the time of evaluation, were used for evaluation. In 145 cases these were healthy test persons in clinical and laboratory respect (group I). 163 test persons were ill, but without any malignous neoplasias (group II), and in 141 patients an ensured malignous neoplasia could be found (group III). From those 308 test persons or patients respectively in group I + II 11 blood smears were falsely classified as positive (= 3.6%). In 5 from 141 cases in group III blood smears were falsely evaluated as negative (= 3.6%). The findings were statistically ensured by the t-test. Clinical parameters of evaluation gained with visual techniques of classification are in accordance with those gained with automatic picture analysis. The reasons for the good separating ability of PW and Ev-I are discussed. Visual techniques of classification are suitable for institutions of all grades of equipment.