Evaluation of Acute Leukaemias by Flow Cytometry and Its Correlation With Diagnosis Using Morphological and Special Staining Techniques

Abstract

Background: Leukaemia can be reliably diagnosed and classified by the simultaneous application of multiple techniques. Cytochemical stains that are cheap and do not require any special instruments are very important in developing countries for the diagnosis of acute leukaemia (AL). Aim: To diagnose AL in all suspected cases by flow cytometry and to correlate the diagnosis with morphological and special staining like myeloperoxidase (MPO) and periodic acid-Sciff (PAS) techniques. Methods and materials: The study participants' peripheral blood smear details and bone marrow aspirate smear morphologic findings, as well as socio-demographic information, were taken from the patients' medical files. In total, 57 newly diagnosed instances of acute leukaemia confirmed by flow cytometry were incorporated into the study, which underwent cytochemical labeling and morphological diagnosis. All patients who gave previous consent had their bone marrow aspirated, and a Wright-stained smear was produced for microscopic inspection, cytochemical staining, and immunophenotyping. In an ethylenediaminetetraacetic acid (EDTA) container, peripheral blood was also drawn for the same purpose. During the entire bone marrow smear examination, we used both MPO and PAS staining techniques. Results: The study was carried out between July 2019 and June 2020. Out of 57 cases in the study, 29 (50.9%) cases on cytochemical analysis of leukaemia using PAS and MPO were diagnosed with acute myeloid leukaemia (AML) and 28 (49.1%) were diagnosed as acute lymphoid leukaemia (ALL). Cytochemical analysis of leukaemia using PAS and MPO rendered the diagnosis in 92.9% of acute leukaemia cases in our study. A total of 25 out of 25 AML cases and 28 out of 32 cases of ALL were correctly diagnosed based on morphology and cytochemical staining. Morphology and cytochemical analysis alone were unable to correctly diagnose a total of four ALL cases. All AML cases that were wrongly diagnosed as ALL were mostly M0 and M1-AML. Conclusion: Morphological staining diagnosis by itself is capable of correctly identifying a large proportion of cases of AL, which comprised 92.98% of total cases. There was also a favorable relationship between findings of diagnosis by flow cytometry and findings of diagnosis by morphology assessment in determining acute leukaemias.