Utility of glass slide morphology (GSM) and whole slide image (WSI) in the diagnosis of acute leukemia (AL) by types

Acute leukemia (AL) is a diverse group of hematological malignancies characterised by the accumulation of immature blast cells in the bone marrow. Accurate classification into acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL) is essential for treatment and prognosis. This study aimed to assess the performance of glass slide morphology (GSM) using a light microscope versus whole slide imaging (WSI) in diagnosing and classifying AL, using flow cytometry as the gold standard test. Peripheral smears and bone marrow aspirates from 97 patients suspected of AL were stained with Romanowsky stain and reviewed by a single hematologist. For GSM, the hematologist was provided with a single slide, which was to be evaluated under a light microscope. For WSI, the Alexapath mobile scanner (ADA1) was used to scan the slides for review by the hematologist. Patient identification was concealed from the interpreting hematologist, and an interval of 2 weeks was set between the review of GSM and WSI of the same patient. The sensitivity and specificity of GSM and WSI were compared to the results of flow cytometry. Out of the 97 patients suspected to have AL, 47 were confirmed to have AL by flow cytometry. Among these, 19 (40.4%) were diagnosed with AML and 28 (59.6%) with ALL. GSM demonstrated high sensitivity (89.4%) and specificity (90.0%) for diagnosing AL, but lower sensitivity in distinguishing AML (57.9%) from ALL (75.0%). Similarly, WSI exhibited a reasonable sensitivity (80.9%) and high specificity (98.0%) for diagnosing AL, but lower sensitivity in differentiating AML (57.9%) and ALL (46.4%). GSM and WSI are reasonable and acceptable techniques for accurately screening AL cases and accelerating referral to tertiary centers of excellence.