A-131 Diagnostic relation between optical microscopy and flow cytometry in chronic lymphoproliferative disease (Cll). And experience of 758 cases in a center in southern Brazil / São Paulo

Abstract Background Early and accurate identification of chronic lymphoproliferative diseases (CLPD) is crucial for guiding patient management. While microscopic evaluation remains a widely used screening tool, its diagnostic accuracy compared to flow cytometry is not well established. This study aimed to assess the reliability of microscopy-based criteria in diagnosing chronic lymphocytic leukemia (CLL) and other lymphoproliferative disorders, using flow cytometry as the reference method . Methods Our laboratory processes between 10,000 and 15,000 white blood cell (WBC) count samples daily using the Mindray BC-6800 Plus hematology analyzer. Over one year, we identified 758 patients whose initial findings met specific criteria suggestive of CLL, including age >50 years, WBC >10,000 cells/µL, platelet abnormalities, and the presence of Gumprecht bodies. Among these, 253 cases were confirmed as lymphoproliferative diseases. Flow cytometry was performed on a subset of these patients for diagnostic confirmation. Results Among the 758 patients initially suspected of having chronic lymphocytic leukemia (CLL) based on microscopic evaluation, 253 were confirmed with a lymphoproliferative disorder through flow cytometry. Of these, 201 were diagnosed with CLL, while 20 were classified as normal/reactive, 18 had inconclusive results, and 14 were diagnosed with other lymphoproliferative disorders (T-cell, Mantle Cell, Plasma Cell). Statistical analysis revealed that the initial microscopy-based assessment demonstrated a sensitivity of 79.4% for detecting CLL. However, its specificity was low at 3.8%, indicating a high rate of false positives. The positive predictive value (PPV) was 28.5%, while the negative predictive value (NPV) was 27.8%. Overall, the concordance rate between microscopic evaluation and flow cytometry was 29.2%. Conclusion This study reinforces the critical role of flow cytometry in diagnosing lymphoproliferative disorders, as it led to a revised diagnosis in at least 20% of cases. The 92% correlation between Mindray BC-6800 Plus results and flow cytometry highlights its potential as a reliable screening tool. These findings highlight the importance of flow cytometry as a confirmatory tool, as it led to a revised diagnosis in at least 20% of cases. Additionally, the Mindray BC-6800 demonstrated a 92% correlation with flow cytometry, underscoring its potential as an initial screening tool for lymphoproliferative disorders.