Utility Of The International Consensus Group Criteria For Manual Peripheral Smear Review Following Automated Blood Cell Analysis & Research Centre, Vijayapur, Karnataka.

Abstract

BACKGROUND Automated haematology analysers have become an integral part of the present day clinical laboratory as they have reduced the number of manual hematology procedures and increased the speed of reporting without sacrificing the quality of the results. Manual smear reviews (MSR), however, still play an important role in identifying morphological abnormalities and to confirm the results of the analysers. It is thus important to make a decision on whether manual smears are necessary for each and every sample. In 2005, the International Society for Laboratory Hematology (ISLH) through the International Consensus Group for Hematology Review (ICGHR), published 41 rules for peripheral smear review after analysis of samples in AHAs, which were review criteria for automated blood count analysis in order to reduce the number of manual smear reviews. OBJECTIVE The objective of this study was to evaluate the effectiveness of the ICGHR criteria for MSR by performing manual peripheral smears for all the samples in the study group following automated blood cell analysis. MATERIALS AND METHODS The study was performed on whole blood samples sent for complete blood count testing to the central laboratory of the Department of Pathology in B.L.D.E.U.’s Shri B. M. Patil Medical College, Hospital and Research Centre, Vijayapur. The study period was from 1st December 2014 to 30th June 2016.Analysis of the blood samples was done on the 6 part differential automated haematology analyser Sysmex XN-1000 and manual peripheral smear review was performed along with a 100-cell manual differential count. Each sample was reviewed according to the adapted ICGHR criteria and the laboratory criteria. Truth tables were prepared for each set of criteria. RESULTS Using the ICGHR criteria, 39.65% samples were true positive, 43.49% were true negative, 7.91% false positive and 8.95% samples were false negative. Accordingly the sensitivity was 81.58%, specificity was 84.61%, 83.38% positive predictive value and, 82.92% negative predictive value. The microscopic smear review rate was 47.56% with an efficiency of 83.14%. Our laboratory criteria revealed a true positivity of 48.02%, true negativity of 21.28%, false positivity of 30.12% and a false negativity of 0.58%. The sensitivity was 98.80%, specificity 41.40%, positive predictive value of 61.46% and, negative predictive value of 97.34%. The microscopic smear review rate was 78.14% with an efficiency of 69.30%. CONCLUSION There was a significant reduction in the microscopic review rates with the application of the ICGHR criteria. However, the false negative rate was higher than the recommended level. Thus the ICGHR criteria can be adapted in laboratories but must be optimized and locally validated for manual smear review before use.