Correlation of Automated Hematology Analyzer Parameters with Peripheral Blood Smear Findings

Background: The automated hematology analyzer has been widely used in modern hematology laboratories with rapid and accurate complete blood count results, making it an indispensable instrument for hematology laboratories. Nevertheless, peripheral blood smear (PBS) examination is still the standard of reference for blood cell morphology and confirmation of abnormal analyzer results. The objective is to test against the correlation of the parameter values obtained from automated hematology analyzer and peripheral blood smear. Material and Methods: This was prospective observational crosssectional study of 100 samples of EDTA blood analysed with fully automated 5 part differential hematology analyzer. Hematological parameters were recorded and instrument generated abnormal flags. Peripheral blood smears were made by the wedge smear method, stained with Leishman stain and analyzed under a microscope. The peripheral smear morphology was correlated with the results obtained from the automated analyzer with suitable statistical analysis. Results: The most common result was: Most respondents were male (58%). The most common analyzer abnormalities were low hemoglobin (44%), elevated RDW (36%), abnormal leukocytes (32%, and abnormal platelets (27%). The overall rate of confirmation of low hemoglobin cases which showed microcytic hypochromic morphology was 90.9% in peripheral smear examination, while for raised RDW cases with anisocytosis, the rate of confirmation was 94.4% and for immature cell flags with immature myeloid cell the rate of confirmation was 88.9%. The automated analyzer achieved a sensitivity of 91%, specificity of 88%, positive predictive value of 89.2%, negative predictive value of 90% and an overall diagnostic accuracy of 89.5%. There were statistically significant correlations between parameters measured by the automated analyzer and peripheral smear parameters (p<0.05). Conclusion: Automated hematology analyzers are found to highly correlate with peripheral smear examination and can be used in routine hematology labs as good screening tools. However, peripheral blood smear analysis will still be essential for checking signs of abnormal flags generated by the analyzer and for assessing morphologic anomalies. Automotive analysis and microscopic examination go hand-in-hand which means that it is a massive improvement in diagnostic accuracy and quality of patient care.

Keywords: Automated haematology analyser, peripheral blood smear, complete blood count, red cell morphology, flags on the analyser, haematology.