Evaluation of laboratory procedures applied for counting platelets

ABSTRACT

Accurate platelets count has an important role in the diagnosis of many haematological disorders such as thrombocytopenia, thrombocytosis as well as for prophylactic platelets transfusion. Therefore, it is necessary to select the most reliable method for such use. These methods include haemocytometry [Manual 1% ammonium oxalate technique], assessment of platelets from well prepared and stained thin blood film and automated analyzer system using KX-21 counter [Sysmex]. Out of 100 blood samples recruited for the study, 31 showed low platelets count, 61 showed normal platelets level and only 8 blood sample showed high platelets concentration. Result showed that the numbers of platelets counted by automated machine were significantly lower than that obtained by both manual methods in samples with less than 150000 platelets/micro L and more than 450000 platelets/micro L. Among normal blood samples, platelets count between 150000 and 450000 platelets/micro L no significant statistical difference detected between the counts obtained by the three techniques. It was concluded that automated blood analyzer systems, which have worldwide distribution, may have problems distinguishing large platelets, or aggregates from other blood cells. The assessment of platelets number using automated counters can reveal the accurate status in samples with normal platelet levels whereas it could not replace the manual ammonium oxalate method particularly in persons with high or low platelets count