Objective: The objective of the present study is to compare values of platelet count on automated coulter with different manual platelet counts and also to ascertain the better methodology to do the same, particularly when coulters are not available in remote areas. Materials &Methods: Platelet count was estimated by four different methods in 75 blood samples(25 each with low, high and normal platelet count) received in Department of Pathology, Dayanand Medical College & Hospital, Ludhiana and compared with platelet count obtained from automated analyzer Beckman coulter LH750. Methods A and B were based on counting the average number of platelets per oil immersion field (OIF) in 10 fields multiplied by factor of 2 and 3 respectively and to yield a platelet count estimate per 109/l. Methods C and D were based on multiplying the total number of platelets counted under 2 high power fields by factor of 2 and 3 respectively. All cases had a normal mean platelet volume (MPV). Statistical Analysis: The agreement between the manual methodologies with each other and each method with the automated count was assessed using the unpaired T-test and correlation coefficient analysis done. Results: Method A and Method C showed no significant differences in platelet values in all the three groups and were comparable to those obtained by automated analyser. Conclusion: Manual methods give reliable and accurate results similar to automated analyser and can be used in rural settings and also automated counts should be counter checked by manual method especially in cases of thrombocytopenia.

Keywords: Platelet; Manual Count; Automated Analyser.