Comparison of three manual platelet count estimation methodologies in peripheral blood smear and their correlation with automated platelet count values

Dr. B.Saranya; Dr. Thamilselvi Ramachandran; Dr. M.Roopmala; Dr. T.Sreneela

Volume : X, Issue : VI, June - 2020

Comparison of three manual platelet count estimation methodologies in peripheral blood smear and their correlation with automated platelet count values

Dr. B. Saranya, Dr. Thamilselvi Ramachandran, Dr. M. Roopmala, Dr. T. Sreneela

Abstract :

INTRODUCTION: Platelets play a key role in hemostasis and thrombosis. The methods commonly used for counting are manually by using a counting chamber, manually by examination of peripheral smear and using a automated hematology analyser. Though automated analyser has replaced the manual methods, Abnormal values generated by automated analyser has to be verified by manual methods. Estimation of platelet counts from peripheral blood smear based on average number of platelets in an oil immersion fluid is approximate and doesn’t give the real number of platelets. Hence other methods for estimation of platelet counts by manual method were advocated for accurate estimation. The alternate estimation method used by Malok.M et al is the average number of platelets per oil immersion field multiplied by patients haemoglobin value in g/dl and then multiplied by 1000 to yield a platelet count estimation in microlitre. Umarani.MK et al estimated the platelet count from peripheral blood smear based on platelet:RBC count. So,the aim of this study is to compare the traditional counting methods done by Malok.M et al and umarani.Mk et al and to correlate the values obtained by these methods with the platelet value of automated platelet counter. MATERIALS AND METHODS: EDTA sample was obtained from 100 patients visiting OPD of Vinayaka missions kirupanandha variyar medical college and Hospitals, Salem and smear is prepared and the platelet values were estimated by using the three manual methods of our study. Method 1: Platelet count in microlitre =average number of platelet in OIF X 15000 Method 2: Platelet count in microlitre =average number of platelets in OIF X Hb in g/dl x 1000 Method 3: Platelet count in 103 /microlitre =number of platelets per 1000 RBC X RBC count in 106/microlitre . The values obtained from the three methods were correlated with the automated analyser value and the correlation coefficient for the three methods were calculated. RESULTS: • Platelet count ranged from Method A: 115000 to 430000, method B: 930000 to 402000, method C: 120000 to 450000 , Automated analyser : 110000 to 432000 • Mean values of the methods Method A: 240782 method B : 218310 method C 225000 , Automated analyser: 240161 • Correlation coefficient Method A: 0.967 Method B: 0.879 Method c: 0.973 CONCLUSION: Method C has a high correlation with the automated analyser value followed by method A. Method B had only a medium level of correlation with the automated analyser value. Method C and A can be used to verify and crosscheck the values of the platelet count given by the automated analyser